Add @final to many unsubclassable stdlib classes (#6299)

stdlib/pyexpat/__init__.pyi

@@ -2,6 +2,7 @@ import pyexpat.errors as errors
 import pyexpat.model as model
 from _typeshed import SupportsRead
 from typing import Any, Callable, Optional, Tuple
+from typing_extensions import final
 
 EXPAT_VERSION: str  # undocumented
 version_info: tuple[int, int, int]  # undocumented
@@ -21,6 +22,7 @@ XML_PARAM_ENTITY_PARSING_ALWAYS: int
 
 _Model = Tuple[int, int, Optional[str], Tuple[Any, ...]]
 
+@final
 class XMLParserType(object):
     def Parse(self, __data: str | bytes, __isfinal: bool = ...) -> int: ...
     def ParseFile(self, __file: SupportsRead[bytes]) -> int: ...