[doc] Add an example for 'non-ascii-file-name'

And move links to related.rst

Author: Pierre-Sassoulas

doc/data/messages/n/non-ascii-file-name/bad/bàd.py

@@ -0,0 +1 @@
+# [non-ascii-file-name]

doc/data/messages/n/non-ascii-file-name/bad/not_bétter.py

@@ -0,0 +1 @@
+# [non-ascii-file-name]

doc/data/messages/n/non-ascii-file-name/details.rst

@@ -0,0 +1,3 @@
+- `PEP 489 <https://peps.python.org/pep-0489/#export-hook-name>`_
+- `PEP 672 <https://peps.python.org/pep-0672/#confusing-features>`_
+- `Python issue 20485 <https://bugs.python.org/issue20485>`_

doc/data/messages/n/non-ascii-file-name/good.py

@@ -43,22 +43,15 @@ class NonAsciiNameChecker(base_checker.BaseChecker):
         ),
         # First %s will always be "file"
         "W2402": (
-            (
-                '%s name "%s" contains a non-ASCII character. PEP 3131 only allows '
-                "non-ascii identifiers, not file names."
-            ),
+            '%s name "%s" contains a non-ASCII character.',
             "non-ascii-file-name",
             (
                 # Some = PyCharm at the time of writing didn't display the non_ascii_name_loł
-                # files and had big troubles with git.
-                # Probably only a bug shows the problem quite good.
-                # That's also why this is a warning and not only a convention!
-                "Some editors don't support non-ASCII file names properly. "
-                "Even though Python supports UTF-8 files since Python 3.5 this isn't "
-                "recommended for interoperability. Further reading:\n"
-                "- https://peps.python.org/pep-0489/#export-hook-name\n"
-                "- https://peps.python.org/pep-0672/#confusing-features\n"
-                "- https://bugs.python.org/issue20485"
+                # files and had big troubles with git. Probably only a bug shows the problem
+                # quite good. That's also why this is a warning and not only a convention!
+                "Under python 3.5, PEP 3131 only allows non-ascii identifiers, not file names."
+                "Since Python 3.5, even though Python supports UTF-8 files, some editors or tools "
+                "don't. "
             ),
         ),
         # First %s will always be "module"

doc/data/messages/n/non-ascii-file-name/good/bad.py

@@ -1 +1 @@
-non-ascii-file-name:1:0:None:None::"File name ""non_ascii_name_loł"" contains a non-ASCII character. PEP 3131 only allows non-ascii identifiers, not file names.":HIGH
+non-ascii-file-name:1:0:None:None::"File name ""non_ascii_name_loł"" contains a non-ASCII character.":HIGH