zsh completion: tweak options for `incoming`, `outgoing` and `rebase` * `incoming --rev` completes _hg_labels, not jsut tags; * `outgoing --rev` completes revrange; * source/dest/base for `rebase` require argument.

zsh completion: update mq commands completion * add qclone command; * qapplied/qunapplied: add --last/--first; * qdiff: add all diff options; * qfold: add --force, --no-backup; * qgoto: add --keep-changes; * qimport: add --git, --push; * qnew: add user- and date-related options; * qpop/qpush: add --keep-changes and --no-backup, drop --name; * qpush: drop deprecated --merge; * qrename: complete only unapplied patches' names; * strip: add --rev, --keep, --bookmark, update descriptions, drop --backup.

zsh completion: add new options for existing commands * backout: add --tool; * bisect: add --extend; * bookmarks: add --inactive; * branches: add --closed; * bundle: add --rev, --all, --branch; * cat: add --decode; * clone: add --updaterev, --branch, --pull and use common-with-qclone opts; * commit: add --close-branch; * diff: add --change, --reverse, --stat, --text, --unified; * export: add --rev; * grep: add --date; * heads: add --topo, --closed; * help: add --extension, --command, --keywords; complete additional help topics also, not commands only; * identify: add --bookmark and remote_opts; * import: add --no-commit, --exact, --import-branch, --date, --user, --similarity and commit options; * log: add --user, --date, --stat, --git, --graph; * manifest: add --rev; * push: add --new-branch; * resolve: add --all, --no-status, --tool and pattern options; * revert: add --date; * serve: add --prefix, --web-conf, --pid-file, --cmdserver, --certificate; * status: add --change; * tag: add --force, --edit, --remove; * tip: add --git; * update: add --check, --date.

zsh completion: add support for convert, graphlog, purge, record extensions

zsh completion: add subrepos options for all supporting commands

zsh completion: add new option groups for options Add clone, date/user, git-style, merge tool, ignore space, log, branch/bookmarks options and use them throughout command completions.

zsh completion: add `forget` and `rollback` commands

zsh completion: complete additional topics for `help`, not commands only

Merge with stable

tests: merging bookmarked heads 45b5eb2941d0 fixed an error that occured when heads being merged were both inactive bookmarks. Add a test for that case.