Change :mc to take delimited pattern
Change :mc to take delimited pattern

This used to take a regexp after a space: ':mc REGEXP'. It now is
delimited, like :g or :s, e.g.

  :mc/REGEXP/FLAGS
  :mc/[a-z]
  :mc/abc/g

UndeadKernel/emacs_doom,UndeadKernel/emacs_doom,UndeadKernel/emacs_doom,UndeadKernel/emacs_doom,hlissner/.emacs.d,hlissner/.emacs.d,hlissner/doom-emacs,hlissner/doom-emacs,hlissner/doom-emacs,hlissner/doom-emacs,hlissner/doom-emacs,UndeadKernel/emacs_doom,hlissner/.emacs.d,hlissner/doom-emacs,hlissner/.emacs.d,hlissner/.emacs.d,UndeadKernel/emacs_doom,hlissner/.emacs.d,hlissner/.emacs.d,hlissner/.emacs.d,hlissner/doom-emacs,UndeadKernel/emacs_doom