[stdlib] Mark constants as Final (#14577)

stdlib/unicodedata.pyi

@@ -1,10 +1,10 @@
 import sys
 from _typeshed import ReadOnlyBuffer
-from typing import Any, Literal, TypeVar, final, overload
+from typing import Any, Final, Literal, TypeVar, final, overload
 from typing_extensions import TypeAlias
 
 ucd_3_2_0: UCD
-unidata_version: str
+unidata_version: Final[str]
 
 if sys.version_info < (3, 10):
     ucnhash_CAPI: Any