BUR #25963 has been approved by @nonamethanks.
mass update cu-no original -> -original
I assumed that this is a leftover from old Danbooru, but for some reason the tag for the webcomic CU-NO is occasionally tagged with Original tag, despite that now we have tags for other webcomic series without "Original" tag applied on it (like Little Nuns (Diva)). So I think this should be removed for the sake of consistency.