Raise obj to the top of its layer.
obj will, then, be the highest one in the layer it belongs to. Object on other layers won't get touched.
See also Efl.Gfx.Stack.stack_above(), Efl.Gfx.Stack.stack_below() and Efl.Gfx.Stack.lower_to_bottom()
Since 1.22
raise_to_top @pure_virtual {}
void efl_gfx_stack_raise_to_top(Eo *obj);