Fix stripping markup from colourless output.

* check_pre_commit_config_frozen.py (strip_rich_markup)

Author: real-yfprojects

check_pre_commit_config_frozen.py

@@ -959,7 +959,7 @@ async def run(self, content: str, file: str) -> Tuple[str, List[Complaint]]:
 def strip_rich_markup(string: str):
     """Remove the markup for the rich library from a string."""
     string = regex_rich_markup_tag.sub("", string)
-    string = regex_rich_markup_escape.sub(lambda m: m[0], string)
+    string = regex_rich_markup_escape.sub("[", string)
     return string