Merge branch 'ms/refs-list'

The "list" subcommand of "git refs" acts as a front-end for
"git for-each-ref".

* ms/refs-list:
  t: add test for git refs list subcommand
  t6300: refactor tests to be shareable
  builtin/refs: add list subcommand
  builtin/for-each-ref: factor out core logic into a helper
  builtin/for-each-ref: align usage string with the man page
  doc: factor out common option

diff --cc builtin/for-each-ref.c
Simple merge

diff --cc t/meson.build
Simple merge