Re: Mark remote `gc --auto` error messages

Lukas Fleischer [off-list ref] writes:

When running `git push`, it might occur that error messages are
transferred from the server to the client. While most messages (those
explicitly sent on sideband 2) are prefixed with "remote:", it seems
that error messages printed during the automatic householding performed
by git-gc(1) are displayed without any additional decoration. Thus, such
messages can easily be misinterpreted as git-gc failing locally, see [1]
for an actual example of where that happened.

Sounds like a sensible goal to me.