Deprecate Finishing Move

BUR #11594 has been rejected.

deprecate finishing_move

Wiki says not to use it, but maybe we want to move the pool to the tag instead?

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 #11594 (forum #218318) has been rejected by @DanbooruBot.