add types.GenericAlias.__mro_entries__ (#13284)

Author: tungol

stdlib/@tests/stubtest_allowlists/common.txt

@@ -459,7 +459,6 @@ turtle.ScrolledCanvas.select_item  # Dynamically created, has unnecessary *args
 
 types.GenericAlias.__call__  # Would be complicated to fix properly, Any could silence problems. #6392
 types.GenericAlias.__getattr__
-types.GenericAlias.__mro_entries__
 
 typing.type_check_only  # typing decorator that is not available at runtime
 

stdlib/types.pyi

@@ -640,6 +640,7 @@ if sys.version_info >= (3, 9):
         def __getitem__(self, typeargs: Any, /) -> GenericAlias: ...
         def __eq__(self, value: object, /) -> bool: ...
         def __hash__(self) -> int: ...
+        def __mro_entries__(self, bases: Iterable[object], /) -> tuple[type, ...]: ...
         if sys.version_info >= (3, 11):
             @property
             def __unpacked__(self) -> bool: ...