Make super() parameters positional-only (#6237)

stdlib/builtins.pyi

@@ -166,9 +166,9 @@ class type(object):
 
 class super(object):
     @overload
-    def __init__(self, t: Any, obj: Any) -> None: ...
+    def __init__(self, __t: Any, __obj: Any) -> None: ...
     @overload
-    def __init__(self, t: Any) -> None: ...
+    def __init__(self, __t: Any) -> None: ...
     @overload
     def __init__(self) -> None: ...