I accidentally made a tag for artist a general tag >< (mashi_fish29)

Hello!
Sorry for bothering, but I accidentally made what was supposed to be an artist tag (mashi_fish29) a general tag. Used in post #5292596. I can't exactly figure out what to do... Would anyone be able to help?

You can fix it by editing the post and adding "artist:" before the tag to change its category, ie. artist:mashi_fish29