Merge 'kn/for-each-tag-branch' into kn/for-each-tag

Merge 'kn/for-each-tag-branch' into kn/for-each-tag

* kn/for-each-tag-branch:
  for-each-ref: add '--contains' option
  ref-filter: implement '--contains' option
  parse-options.h: add macros for '--contains' option
  parse-option: rename parse_opt_with_commit()
  for-each-ref: add '--merged' and '--no-merged' options
  ref-filter: implement '--merged' and '--no-merged' options
  ref-filter: add parse_opt_merge_filter()
  for-each-ref: add '--points-at' option
  ref-filter: implement '--points-at' option
  tag: libify parse_opt_points_at()
  t6302: for-each-ref tests for ref-filter APIs