Add __hash__ for a bunch of types that set it to None (#13286)

stdlib/argparse.pyi

@@ -2,7 +2,7 @@ import sys
 from _typeshed import sentinel
 from collections.abc import Callable, Generator, Iterable, Sequence
 from re import Pattern
-from typing import IO, Any, Final, Generic, NewType, NoReturn, Protocol, TypeVar, overload
+from typing import IO, Any, ClassVar, Final, Generic, NewType, NoReturn, Protocol, TypeVar, overload
 from typing_extensions import Self, TypeAlias, deprecated
 
 __all__ = [
@@ -456,6 +456,7 @@ class Namespace(_AttributeHolder):
     def __setattr__(self, name: str, value: Any, /) -> None: ...
     def __contains__(self, key: str) -> bool: ...
     def __eq__(self, other: object) -> bool: ...
+    __hash__: ClassVar[None]  # type: ignore[assignment]
 
 class FileType:
     # undocumented