Update character names

BUR #15840 has been rejected.

create alias momonosuke_(one_piece) -> kouzuki_momonosuke
create alias kouzuki_hiyori -> hiyori_kouzuki
create alias kouzuki_oden -> oden_kouzuki

They are not well written.

It looks like Danbooru prefers using the Kunrei-Shiki romanization method which includes extended vowels.
光月 in kana is こうずき ko-u-zu-ki. It might look odd to an English person (especially when we've collectively agreed to drop bar accents (Kōzuki) intended to show extended vowels from Hepburn romanization) but that's how it is.

Danbooru actually prefers official romanizations in most cases, and only in case they're absent, inconsistent or unpopular, it goes with this specific method.

That being said, I am not familiar with One Piece - are they consistently romanized without ou in official media?

It would be good to change the title of this topic to mention One Piece.

The name is 光月おでん, not おでん光月.

The bulk update request #15840 (forum #236433) has been rejected by @nonamethanks.