[stdlib] Mark constants as Final (#14577)

stdlib/wsgiref/headers.pyi

@@ -1,10 +1,10 @@
 from re import Pattern
-from typing import overload
+from typing import Final, overload
 from typing_extensions import TypeAlias
 
 _HeaderList: TypeAlias = list[tuple[str, str]]
 
-tspecials: Pattern[str]  # undocumented
+tspecials: Final[Pattern[str]]  # undocumented
 
 class Headers:
     def __init__(self, headers: _HeaderList | None = None) -> None: ...