fix type.__or__ (#14813)

Co-authored-by: Alex Waygood <[email protected]>

Author: KotlinIsland

stdlib/builtins.pyi

@@ -226,8 +226,10 @@ class type:
     @classmethod
     def __prepare__(metacls, name: str, bases: tuple[type, ...], /, **kwds: Any) -> MutableMapping[str, object]: ...
     if sys.version_info >= (3, 10):
-        def __or__(self, value: Any, /) -> types.UnionType: ...
-        def __ror__(self, value: Any, /) -> types.UnionType: ...
+        # `int | str` produces an instance of `UnionType`, but `int | int` produces an instance of `type`,
+        # and `abc.ABC | abc.ABC` produces an instance of `abc.ABCMeta`.
+        def __or__(self: _typeshed.Self, value: Any, /) -> types.UnionType | _typeshed.Self: ...
+        def __ror__(self: _typeshed.Self, value: Any, /) -> types.UnionType | _typeshed.Self: ...
     if sys.version_info >= (3, 12):
         __type_params__: tuple[TypeVar | ParamSpec | TypeVarTuple, ...]
     __annotations__: dict[str, AnnotationForm]