Merge branch 'jk/describe-omit-some-refs'

Merge branch 'jk/describe-omit-some-refs'

"git describe" and "git name-rev" have been taught to take more
than one refname patterns to restrict the set of refs to base their
naming output on, and also learned to take negative patterns to
name refs not to be used for naming via their "--exclude" option.

* jk/describe-omit-some-refs:
  describe: teach describe negative pattern matches
  describe: teach --match to accept multiple patterns
  name-rev: add support to exclude refs by pattern match
  name-rev: extend --refs to accept multiple patterns
  doc: add documentation for OPT_STRING_LIST