Remove more Python 3.8 cruft (#13787)

stdlib/types.pyi

@@ -11,13 +11,14 @@ from collections.abc import (
     Iterable,
     Iterator,
     KeysView,
+    Mapping,  # noqa: Y022
     MutableSequence,
     ValuesView,
 )
 from importlib.machinery import ModuleSpec
 
 # pytype crashes if types.MappingProxyType inherits from collections.abc.Mapping instead of typing.Mapping
-from typing import Any, ClassVar, Literal, Mapping, TypeVar, final, overload  # noqa: Y022
+from typing import Any, ClassVar, Literal, TypeVar, final, overload
 from typing_extensions import ParamSpec, Self, TypeAliasType, TypeVarTuple, deprecated
 
 __all__ = [