Merge branch 'rs/parseopt-short-help'

Make "-h" command line option work more consistently in all commands. * rs/parseopt-short-help: show-ref: stop using PARSE_OPT_NO_INTERNAL_HELP grep: stop using PARSE_OPT_NO_INTERNAL_HELP parse-options: allow -h as a short option parse-options: inline parse_options_usage() at its only remaining caller parse-options: deduplicate parse_options_usage() calls