Release groups can't be deleted manually, but they still have a /delete page you can only access if you navigate to it, which just tells you how autoremoval works. I can see the use of documenting autoremoval, but that should be done in a place which people will find without having to try and append /delete to an URL, so I added https://wiki.musicbrainz.org/How_to_Remove_Entities for this and I think we should now remove this page.