Type and mark as final module-level dunders not meant to be overwritten in stdlib/ (#9709)

stdlib/pydoc.pyi

@@ -6,16 +6,16 @@ from collections.abc import Callable, Container, Mapping, MutableMapping
 from reprlib import Repr
 from types import MethodType, ModuleType, TracebackType
 from typing import IO, Any, AnyStr, NoReturn, TypeVar
-from typing_extensions import TypeGuard
+from typing_extensions import Final, TypeGuard
 
 __all__ = ["help"]
 
 _T = TypeVar("_T")
 
-__author__: str
-__date__: str
-__version__: str
-__credits__: str
+__author__: Final[str]
+__date__: Final[str]
+__version__: Final[str]
+__credits__: Final[str]
 
 def pathdirs() -> list[str]: ...
 def getdoc(object: object) -> str: ...