[LANGUAGE] Adds buttons to Hedy (hedyorg#3748)

**Description**

Adds a new rule to the grammar to make it possible to define a button, with the syntax:
```python
hello is button
```

Changes the grammar rule ```ifpressed``` so that instead of a keyboard character the name of a button can be used, with the expected outcome.

Changes the front-end HTML templates to add a div containing the user created buttons just below the output screen.

**Fixes**

This PR fixes hedyorg#3678.

Always link the number of the issue or of the discussion that your PR concerns.
Tip, if you use the words fixes before the issue number in this description, the related issue will automatically close then the PR is merged! 

**How to test**

In level 5 run the following Hedy code:
```python
hello is button

if hello is pressed print "Hello world!"
```
A button should appear, and pressing the button should result in the string `Hello world!` appearing in the output and the program terminating.

**Checklist**
Done? Check if you have it all in place using this list:*
  
- [x] Contains one of the PR categories in the name
- [x] Describes changes in the format above
- [x] Links to an existing issue or discussion 
- [x] Has a "How to test" section

If you're unsure about any of these, don't hesitate to ask. We're here to help!

content/keywords/ar.yaml

@@ -53,4 +53,5 @@ green: اخضر
 orange: برتقالي
 pink: زهري
 pressed: pressed
+button: button
 not in: not in

content/keywords/bg.yaml

@@ -53,4 +53,5 @@ red: червено
 white: бяло
 yellow: жълто
 pressed: pressed
+button: button
 not in: not in

content/keywords/bn.yaml

@@ -53,4 +53,5 @@ pink: pink
 white: white
 yellow: yellow
 pressed: pressed
+button: button
 not in: not in

content/keywords/cs.yaml

@@ -53,4 +53,5 @@ red: red
 white: white
 yellow: yellow
 pressed: pressed
+button: button
 not in: not in

content/keywords/de.yaml

@@ -53,4 +53,5 @@ red: Rot
 white: Weiß
 yellow: Gelb
 pressed: gedrückt
+button: button
 not in: nicht in

content/keywords/el.yaml

@@ -53,4 +53,5 @@ red: red
 white: white
 yellow: yellow
 pressed: pressed
+button: button
 not in: not in

content/keywords/en.yaml

@@ -54,3 +54,4 @@ length: length
 comma: ','
 quote: "'"
 pressed: pressed
+button: button

content/keywords/eo.yaml

@@ -53,4 +53,5 @@ length: longo
 comma: ','
 quote: "'"
 pressed: pressed
+button: button
 not in: not in

content/keywords/es.yaml

@@ -53,4 +53,5 @@ purple: púrpura
 red: rojo
 white: blanco
 pressed: presionada
+button: button
 not in: no en

content/keywords/et.yaml

@@ -53,4 +53,5 @@ elif: muidukui
 comma: ','
 quote: "'"
 pressed: pressed
+button: button
 not in: not in

content/keywords/fa.yaml

@@ -53,4 +53,5 @@ red: قرمز
 white: سفید
 yellow: زرد
 pressed: pressed
+button: button
 not in: not in

content/keywords/fi.yaml

@@ -54,3 +54,4 @@ comma: ','
 quote: "'"
 pressed: painettu
 not in: not in
+button: button

content/keywords/fr.yaml

@@ -53,4 +53,5 @@ red: rouge
 white: blanc
 yellow: jaune
 pressed: pressed
+button: button
 not in: not in

content/keywords/fy.yaml

@@ -53,4 +53,5 @@ yellow: yellow
 color: color
 black: black
 pressed: pressed
+button: button
 not in: not in

content/keywords/he.yaml

@@ -53,4 +53,5 @@ elif: אחרתאם
 comma: ','
 quote: "'"
 pressed: pressed
+button: button
 not in: not in

content/keywords/hi.yaml

@@ -53,4 +53,5 @@ red: red
 white: white
 yellow: yellow
 pressed: pressed
+button: button
 not in: not in

content/keywords/hu.yaml

@@ -53,4 +53,5 @@ green: zöld
 orange: narancs
 yellow: sárga
 pressed: pressed
+button: button
 not in: not in

content/keywords/id.yaml

@@ -53,4 +53,5 @@ red: red
 white: white
 yellow: yellow
 pressed: pressed
+button: button
 not in: not in

content/keywords/it.yaml

@@ -53,4 +53,5 @@ red: rosso
 white: bianco
 yellow: giallo
 pressed: pressed
+button: button
 not in: not in

content/keywords/ja.yaml

@@ -53,4 +53,5 @@ to: to
 0: '0'
 comma: ','
 pressed: pressed
+button: button
 not in: not in

content/keywords/ko.yaml

@@ -53,4 +53,5 @@ length: length
 comma: ','
 quote: "'"
 pressed: pressed
+button: button
 not in: not in

content/keywords/nb_NO.yaml

@@ -53,4 +53,5 @@ red: red
 white: white
 yellow: yellow
 pressed: pressed
+button: button
 not in: not in

content/keywords/nl.yaml

@@ -53,4 +53,5 @@ length: lengte
 comma: ','
 quote: "'"
 pressed: ingedrukt
+button: knop
 not in: not in

content/keywords/pa_PK.yaml

@@ -53,4 +53,5 @@ length: لمبائی
 comma: '،'
 quote: "'"
 pressed: pressed
+button: button
 not in: not in

content/keywords/pl.yaml

@@ -52,5 +52,6 @@ purple: fioletowy
 red: czerwony
 white: biały
 yellow: żółty
+button: button
 pressed: naciśnięty
 not in: nie w

content/keywords/pt_BR.yaml

@@ -53,4 +53,5 @@ pink: rosa
 white: branco
 yellow: amarelo
 pressed: pressed
+button: button
 not in: not in

content/keywords/pt_PT.yaml

@@ -53,4 +53,5 @@ red: vermelho
 white: branco
 yellow: amarelo
 pressed: pressed
+button: button
 not in: not in

content/keywords/ru.yaml

@@ -53,4 +53,5 @@ red: красный
 white: белый
 yellow: жёлтый
 pressed: нажмите
+button: button
 not in: not in

content/keywords/sq.yaml

@@ -53,4 +53,5 @@ length: gjatësia
 comma: ','
 quote: "'"
 pressed: shtypur
+button: button
 not in: not in

content/keywords/sv.yaml

@@ -53,4 +53,5 @@ length: längd
 comma: ','
 quote: "'"
 pressed: pressed
+button: button
 not in: not in

content/keywords/sw.yaml

@@ -53,4 +53,5 @@ orange: orange
 pink: pink
 purple: purple
 pressed: pressed
+button: button
 not in: not in

content/keywords/th.yaml

@@ -53,4 +53,5 @@ length: ความยาว
 comma: ','
 quote: "'"
 pressed: pressed
+button: button
 not in: not in

content/keywords/tl.yaml

@@ -54,3 +54,4 @@ comma: ','
 quote: "'"
 pressed: pressed
 not in: not in
+button: button

content/keywords/tn.yaml

@@ -53,4 +53,5 @@ length: length
 comma: ','
 quote: "'"
 pressed: pressed
+button: button
 not in: not in

content/keywords/tr.yaml

@@ -53,4 +53,5 @@ red: red
 white: white
 yellow: yellow
 pressed: pressed
+button: button
 not in: not in

content/keywords/uk.yaml

@@ -53,4 +53,5 @@ is: це
 sleep: почекай
 add: додай
 pressed: натиснув
+button: button
 not in: не в

content/keywords/ur.yaml

@@ -53,4 +53,5 @@ length: length
 comma: ','
 quote: "'"
 pressed: pressed
+button: button
 not in: not in

content/keywords/vi.yaml

@@ -54,3 +54,4 @@ comma: ','
 quote: "'"
 pressed: pressed
 not in: not in
+button: button

content/keywords/zh_Hans.yaml

@@ -53,4 +53,5 @@ red: 红色
 white: 白色
 yellow: 黄色
 pressed: pressed
+button: button
 not in: not in

grammars/keywords-ar.lark

@@ -42,3 +42,4 @@ _WHILE: ( "ـ"* "ب" "ـ"* "ي" "ـ"* "ن" "ـ"* "م" "ـ"* "ا" "ـ"*  | "while
 _LENGTH:  "ـ"* "ط" "ـ"* "و" "ـ"* "ل" "ـ"*  | "length"
 _COLOR : ( "ـ"* "ل" "ـ"* "و" "ـ"* "ن" "ـ"*  | "color") _SPACE?
 _PRESSED: ( "ـ"* "p" "ـ"* "r" "ـ"* "e" "ـ"* "s" "ـ"* "s" "ـ"* "e" "ـ"* "d" "ـ"*  | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-bg.lark

@@ -42,3 +42,4 @@ _WHILE: ("докато" | "while") _SPACE
 _LENGTH: "дължина" | "length"
 _COLOR : ("цвят" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-de.lark

@@ -42,3 +42,4 @@ _WHILE: ("solange" | "while") _SPACE
 _LENGTH: "Länge" | "length"
 _COLOR : ("Farbe" | "color") _SPACE?
 _PRESSED: ("gedrückt" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-en.lark

@@ -42,3 +42,4 @@ _WHILE: ("while" | "while") _SPACE
 _LENGTH: "length" | "length"
 _COLOR : ("color" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-eo.lark

@@ -42,3 +42,4 @@ _WHILE: ("dum" | "while") _SPACE
 _LENGTH: "longo" | "length"
 _COLOR : ("koloro" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-es.lark

@@ -42,3 +42,4 @@ _WHILE: ("mientras" | "while") _SPACE
 _LENGTH: "longitud" | "length"
 _COLOR : ("color" | "color") _SPACE?
 _PRESSED: ("presionada" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-et.lark

@@ -42,3 +42,4 @@ _WHILE: ("senikui" | "while") _SPACE
 _LENGTH: "pikkus" | "length"
 _COLOR : ("värv" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-fa.lark

@@ -42,3 +42,4 @@ _WHILE: ("while" | "while") _SPACE
 _LENGTH: "length" | "length"
 _COLOR : ("رنگ" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-fi.lark

@@ -42,3 +42,4 @@ _WHILE: ("kun" | "while") _SPACE
 _LENGTH: "pituus" | "length"
 _COLOR : ("väri" | "color") _SPACE?
 _PRESSED: ("painettu" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-fr.lark

@@ -42,3 +42,4 @@ _WHILE: ("tant que" | "while") _SPACE
 _LENGTH: "longueur" | "length"
 _COLOR : ("couleur" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-he.lark

@@ -42,3 +42,4 @@ _WHILE: ("כלעוד" | "while") _SPACE
 _LENGTH: "אורך" | "length"
 _COLOR : ("צבע" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-hi.lark

@@ -42,3 +42,4 @@ _WHILE: ("व्हाइल" | "while") _SPACE
 _LENGTH: "लंबाई" | "length"
 _COLOR : ("color" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-hu.lark

@@ -42,3 +42,4 @@ _WHILE: ("amíg" | "while") _SPACE
 _LENGTH: "hossz" | "length"
 _COLOR : ("szín" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-id.lark

@@ -42,3 +42,4 @@ _WHILE: ("selama" | "while") _SPACE
 _LENGTH: "panjang" | "length"
 _COLOR : ("warna" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-it.lark

@@ -42,3 +42,4 @@ _WHILE: ("mentre" | "while") _SPACE
 _LENGTH: "lunghezza" | "length"
 _COLOR : ("colore" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-ja.lark

@@ -42,3 +42,4 @@ _WHILE: ("while" | "while") _SPACE
 _LENGTH: "length" | "length"
 _COLOR : ("いろ" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-nb_NO.lark

@@ -42,3 +42,4 @@ _WHILE: ("mens" | "while") _SPACE
 _LENGTH: "lengde" | "length"
 _COLOR : ("color" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-nl.lark

@@ -42,3 +42,4 @@ _WHILE: ("zolang" | "while") _SPACE
 _LENGTH: "lengte" | "length"
 _COLOR : ("kleur" | "color") _SPACE?
 _PRESSED: ("ingedrukt" | "pressed") _SPACE?
+_BUTTON: ("knop" | "button") _SPACE?

grammars/keywords-pa_PK.lark

@@ -1,4 +1,5 @@
-_PRINT: ("چپائی" | "print") _SPACE?
+
+_BUTTON: ("button" | "button") _SPACE?_PRINT: ("چپائی" | "print") _SPACE?
 _ASK: ("سوال" | "ask") _SPACE?
 _ECHO: ("فیر" | "echo") _SPACE?
 _FORWARD: ("اگے" | "forward") _SPACE?
@@ -42,3 +43,4 @@ _WHILE: ("جدکہ" | "while") _SPACE
 _LENGTH: "لمبائی" | "length"
 _COLOR : ("رنگ" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-pl.lark

@@ -41,4 +41,5 @@ _OR: _SPACE ("lub" | "or") _SPACE
 _WHILE: ("dopóki" | "while") _SPACE
 _LENGTH: "długość" | "length"
 _COLOR : ("kolor" | "color") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?
 _PRESSED: ("naciśnięty" | "pressed") _SPACE?

grammars/keywords-pt_BR.lark

@@ -42,3 +42,4 @@ _WHILE: ("enquanto" | "while") _SPACE
 _LENGTH: "comprimento" | "length"
 _COLOR : ("cor" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-pt_PT.lark

@@ -42,3 +42,4 @@ _WHILE: ("enquanto" | "while") _SPACE
 _LENGTH: "comprimento" | "length"
 _COLOR : ("cor" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-ru.lark

@@ -42,3 +42,4 @@ _WHILE: ("пока" | "while") _SPACE
 _LENGTH: "длина" | "length"
 _COLOR : ("цвет" | "color") _SPACE?
 _PRESSED: ("нажмите" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-sq.lark

@@ -1,4 +1,5 @@
-_PRINT: ("print" | "print") _SPACE?
+
+_BUTTON: ("button" | "button") _SPACE?_PRINT: ("print" | "print") _SPACE?
 _ASK: ("pyet" | "ask") _SPACE?
 _ECHO: ("përsërit" | "echo") _SPACE?
 _FORWARD: ("përpara" | "forward") _SPACE?
@@ -42,3 +43,4 @@ _WHILE: ("derisa" | "while") _SPACE
 _LENGTH: "gjatësia" | "length"
 _COLOR : ("ngjyrë" | "color") _SPACE?
 _PRESSED: ("shtypur" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-sv.lark

@@ -42,3 +42,4 @@ _WHILE: ("medans" | "while") _SPACE
 _LENGTH: "längd" | "length"
 _COLOR : ("färg" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-template.lark

@@ -42,3 +42,4 @@ _WHILE: ({while} | "while") _SPACE
 _LENGTH: {length} | "length"
 _COLOR : ({color} | "color") _SPACE?
 _PRESSED: ({pressed} | "pressed") _SPACE?
+_BUTTON: ({button} | "button") _SPACE?

grammars/keywords-th.lark

@@ -42,3 +42,4 @@ _WHILE: ("while" | "while") _SPACE
 _LENGTH: "ความยาว" | "length"
 _COLOR : ("สี" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-tn.lark

@@ -42,3 +42,4 @@ _WHILE: ("while" | "while") _SPACE
 _LENGTH: "length" | "length"
 _COLOR : ("color" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-tr.lark

@@ -42,3 +42,4 @@ _WHILE: ("iken" | "while") _SPACE
 _LENGTH: "uzunluk" | "length"
 _COLOR : ("color" | "color") _SPACE?
 _PRESSED: ("pressed" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?

grammars/keywords-uk.lark

@@ -42,3 +42,4 @@ _WHILE: ("тоді як" | "while") _SPACE
 _LENGTH: "довжина" | "length"
 _COLOR : ("колір" | "color") _SPACE?
 _PRESSED: ("натиснув" | "pressed") _SPACE?
+_BUTTON: ("button" | "button") _SPACE?