Jujutsu now creates colocated repositories by default (repositories

which can be treated as either jj or git repos), and the

remote_bookmarks template method is now returning the git-tracking

bookmark in addition to the real remote ref name. This broke the remote

bookmark detection because we were now getting results as "main@origin

main@git" instead of just "main@origin", which didn't parse correctly

when passed in to other commands.
This change fixes this by updating the commands that fetch remote

bookmarks to filter out the "git" remote from the results. Things which

expect to fetch a single result will now also split lines and choose the

first result. In practice what was there before should be fine after the

filter change, but I'd rather be cautious.

Unit tests pass again.