[mixed-line-endings] Create the initial documentation (#8994)

Refs #5953

Author: Pierre-Sassoulas

.gitattributes

@@ -4,3 +4,4 @@ tests/input/** -text
 tests/**/data/** -text
 tests/regrtest_data/** -text
 doc/data/messages/u/unexpected-line-ending-format/bad.py -text
+doc/data/messages/m/mixed-line-endings/bad.py -text

doc/data/messages/m/mixed-line-endings/bad.py

@@ -0,0 +1,2 @@
+print("Hello")  # CRLF (\r\n)
+print("World")  # LF (\n) # [mixed-line-endings]

doc/data/messages/m/mixed-line-endings/details.rst

@@ -0,0 +1,2 @@
+print("Hello")  # CRLF (\r\n)
+print("World")  # CRLF (\r\n)

doc/data/messages/m/mixed-line-endings/good.py

@@ -0,0 +1,2 @@
+print("Hello")  # LF (\n)
+print("World")  # LF (\n)

doc/data/messages/m/mixed-line-endings/good/full_crlf.py

@@ -0,0 +1,3 @@
+- `History of CRLF and LF <https://stackoverflow.com/a/6521730/2519059>`_
+- `Dealing with line endings in Git <https://stackoverflow.com/a/10855862/2519059>`_
+- `A Collection of Useful .gitattributes Templates <https://github.com/alexkaratarakis/gitattributes>`_

doc/data/messages/m/mixed-line-endings/good/full_lf.py

@@ -1,2 +1,2 @@
-print("Sometimes I drink soda.")  # CRLF # [unexpected-line-ending-format]
-print("Sometimes I drink sulfuric acid.")  # CRLF # [unexpected-line-ending-format]
+print("I'm drinking tea!")  # CRLF (\r\n) # [unexpected-line-ending-format]
+print("I'm drinking water!")  # CRLF (\r\n) # [unexpected-line-ending-format]

doc/data/messages/m/mixed-line-endings/related.rst

@@ -1,2 +1,2 @@
-print("I'm drinking tea!")  # LF
-print("I'm drinking water!")  # LF
+print("I'm drinking tea!")  # LF (\n)
+print("I'm drinking water!")  # LF (\n)