Encode string escape chars with code formatting (dotnet#6261)

* Encode string escape chars with code formatting

This makes it a bit more clear how to use them.

* Fix up statement of result

docs/fsharp/language-reference/strings.md

@@ -15,14 +15,14 @@ String literals are delimited by the quotation mark (") character. The backslash
 
 |Character|Escape sequence|
 |---------|---------------|
-|Backspace|\b|
-|Newline|\n|
-|Carriage return|\r|
-|Tab|\t|
-|Backslash|\\|
-|Quotation mark|\"|
-|Apostrophe|\'|
-|Unicode character|\u*XXXX* or \U*XXXXXXXX* (where *X* indicates a hexadecimal digit)|
+|Backspace|`\b`|
+|Newline|`\n`|
+|Carriage return|`\r`|
+|Tab|`\t`|
+|Backslash|`\\`|
+|Quotation mark|`\"`|
+|Apostrophe|`\'`|
+|Unicode character|`\uXXXX` or `\UXXXX` (where `X` indicates a hexadecimal digit)|
 
 If preceded by the @ symbol, the literal is a verbatim string. This means that any escape sequences are ignored, except that two quotation mark characters are interpreted as one quotation mark character.
 
@@ -36,7 +36,7 @@ let xmlFragment1 = @"<book author=""Milton, John"" title=""Paradise Lost"">"
 let xmlFragment2 = """<book author="Milton, John" title="Paradise Lost">"""
 ```
 
-In code, strings that have line breaks are accepted and the line breaks are interpreted literally as newlines, unless a backslash character is the last character before the line break. Leading whitespace on the next line is ignored when the backslash character is used. The following code produces a string `str1` that has value `"abc\n     def"` and a string `str2` that has value `"abcdef"`.
+In code, strings that have line breaks are accepted and the line breaks are interpreted literally as newlines, unless a backslash character is the last character before the line break. Leading whitespace on the next line is ignored when the backslash character is used. The following code produces a string `str1` that has value `"abc\ndef"` and a string `str2` that has value `"abcdef"`.
 
 [!code-fsharp[Main](../../../samples/snippets/fsharp/lang-ref-1/snippet1001.fs)]