Don't treat *_(cosplay) tags as being invisibly aliased when a character tag is aliased. For example,
if toosaka_rin is aliased to tohsaka_rin, and toosaka_rin_(cosplay) is later added to a post, don't
magically translate the tag to tohsaka_rin_(cosplay). Instead, treat it as an error to create a
*_(cosplay) tag for an aliased character tag.
This removes some of the complexity and magic behavior surrounding *_(cosplay) tags.