adding __contains__ stub to displayio.Group

Author: FoamyGuy

shared-bindings/displayio/Group.c

@@ -249,6 +249,10 @@ STATIC mp_obj_t displayio_group_obj_remove(mp_obj_t self_in, mp_obj_t layer) {
 MP_DEFINE_CONST_FUN_OBJ_2(displayio_group_remove_obj, displayio_group_obj_remove);
 
 //|     def __bool__(self) -> bool: ...
+//|     def __contains__(
+//|         self,
+//|         item: Union[vectorio.Circle, vectorio.Rectangle, vectorio.Polygon, Group, TileGrid],
+//|     ) -> bool: ...
 //|     def __len__(self) -> int:
 //|         """Returns the number of layers in a Group"""
 //|         ...