Merge branch 'nd/parseopt-completion' into next

Teach parse-options API an option to help the completion script,
and make use of the mechanism in command line completion.

* nd/parseopt-completion:
completion: more subcommands in _git_notes()
completion: complete --{reuse,reedit}-message= for all notes subcmds
completion: simplify _git_notes
completion: don't set PARSE_OPT_NOCOMPLETE on --rerere-autoupdate

diff --cc contrib/completion/git-completion.bash
Simple merge