Classical guidelines require using ; in join phrases, followed by a space. This makes it pretty common, so it should be added to our join phrase cleanup:

https://github.com/metabrainz/musicbrainz-server/blob/65f54a1247f0c1003b7dc9cc0a47b96463b97794/root/static/scripts/edit/MB/Control/ArtistCredit.js#L54

(this code seems to not be running at the moment, but that doesn't mean this shouldn't be added so that it works once the code itself is fixed properly).