histedit: more precise user message when changeset is missing
Now that we explicitly detect duplicated changesets, we can explicitly
detect missing ones. We cover the same cases as before, some others
and we offer a better error message in all cases.
$ "$TESTDIR/hghave" inotify || exit 80
$ hg init
$ echo "[extensions]" > .hg/hgrc
$ echo "inotify=" >> .hg/hgrc
$ hg inserve -d --pid-file .hg/inotify.pid
$ echo a > a
$ hg ci -Aqm0
$ hg co -q null
$ hg co -q
$ hg st
$ cat a
a
$ "$TESTDIR/killdaemons.py" .hg/inotify.pid