Merge branch 'nd/parse-options-aliases'

Attempt to use an abbreviated option in "git clone --recurs" is responded by a request to disambiguate between --recursive and --recurse-submodules, which is bad because these two are synonyms. The parse-options API has been extended to define such synonyms more easily and not produce an unnecessary failure. * nd/parse-options-aliases: parse-options: don't emit "ambiguous option" for aliases