Seems I was under the mistaken impression that all customizations with a
"CHANGED" state get saved when hitting C-x C-s (`Custom-save'), which is
obviously not the case. Thus, I think it's best not to mislead users by
spoofing the modification state because the only benefit of doing so now
is that carats aren't automatically thrown open on module-var widgets,
which is a comparatively minor annoyance. The attached patch reverts
this spoofing nonsense and also restores a working toggle button so
users again have the option of dismissing the warning.