Tag alias: finger_to_chin -> finger_on_own_chin

BUR #4175 has been approved by @evazion.

create alias finger_to_chin -> finger_to_own_chin

Consistency with finger to another's chin, hand on own chin, and hand on another's chin.

I would say "we should make sure there aren't any mistakenly tagged finger to chin instead of finger to another's chin before we make the alias" but I checked the tag history and you just did that, so it sounds like a good idea to me.

EDIT: I think this would work better as a rename, rather than an alias.

The bulk update request #4175 (forum #177321) has been approved by @evazion.