alias frilled_boots -> frilled_footwear

BUR #7569 has been rejected.

create alias frilled_boots -> frilled_footwear

for consistency

The boots implication needs to be removed first.

Also, topic #19453 got approved, so we might end up splitting footwear tags too in the end.

This bulk update request is pending automatic rejection in 5 days.

This bulk update request has been rejected because it was not approved within 45 days.

The bulk update request #7569 (forum #198449) has been rejected by @DanbooruBot.