Clothes on/over head alias

BUR #18702 has been rejected.

create alias jacket_over_head -> jacket_on_head

All posts with two similar-looking existing tags show jackets on character's head.
I think it's better to alias them into on_head option in order to create consistency with similar *_on_head tags such as eyewear_on_head.

There's also shirt_over_head but not shirt on head.

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 #18702 (forum #249131) has been rejected by @DanbooruBot.