Change unused AbstractGroup layer argument type to optional int

Author: aatle

buildconfig/stubs/pygame/sprite.pyi

@@ -88,7 +88,7 @@ class AbstractGroup(Generic[_SpriteT]):
     def __iter__(self) -> Iterator[_SpriteT]: ...
     def __bool__(self) -> bool: ...
     def __contains__(self, item: Any) -> bool: ...
-    def add_internal(self, sprite: _SpriteT, layer: None = None) -> None: ...
+    def add_internal(self, sprite: _SpriteT, layer: Optional[int] = None) -> None: ...
     def remove_internal(self, sprite: _SpriteT) -> None: ...
     def has_internal(self, sprite: _SpriteT) -> bool: ...
     def copy(self) -> Self: ...