Make this build with gtk-4.20

Author: rhx

Sources/Gtk/Gtk-4.0.sed

@@ -51,3 +51,4 @@ s/GLib.RefSListRef<ObjectRef>/GLib.RefSListRef<GLibObject.ObjectRef>/
 s/free(UnsafeMutableRawPointer/systemFree(UnsafeMutableRawPointer/
 s/func load(from path: UnsafePointer<CChar>/func loadFrom(file path: UnsafePointer<CChar>/
 s/func load(from string: UnsafePointer<CChar>/func loadFrom(string: UnsafePointer<CChar>/
+s/gtk_menu_button_set_popover(\([^,]*\), \([^)]*\)\.popover_ptr)/gtk_menu_button_set_popover(\1, \2.widget_ptr)/g