Merging Round1 and Round One tags

BUR #51973 has been approved by @evazion.

create alias round_one -> round1

Currently Round1 and Round One exist as duplicate tags. This BUR will merge them. I believe Round1 should be the main tag name due to every image being specifically Round1 collabs or depictions of Round1 merch/locations.

The bulk update request #51973 (forum #404065) has been approved by @evazion.

From what I can tell, there haven't been any mistags of Round One, so it might not be necessary, but would it make sense to swap the alias for something like round_one_(arcade)? As someone unfamiliar with the brand, Round One by itself makes me think of fighting games and combat sports.