Merge branch 'ib/rev-parse-parseopt-argh'

Teaches the "rev-parse --parseopt" mechanism used by scripted Porcelains to parse command line options and give help text how to supply argv-help (the placeholder string for an option parameter, e.g. "key-id" in "--gpg-sign=<key-id>"). * ib/rev-parse-parseopt-argh: t1502: protect runs of SPs used in the indentation rev-parse --parseopt: option argument name hints