Implement compatibility commands ef-themes-select-{dark,light}

We used to have those and I thought they were back in after the
redesign on top of Modus. But I never did that until the latest
commits to modus-themes.git.

This:

    commit a472f546459a80f3c95255118831d35a6dcbddf0
    Author: Protesilaos Stavrou <info@protesilaos.com>
    Date:   Sat Nov 22 16:47:08 2025 +0200

      Update modus-themes-define-derivative-command-known-suffixes to include select-{dark,light}

And this:

    commit c270cd8f5ea431534b5e9d6455239d890d9ed055
    Author: Protesilaos Stavrou <info@protesilaos.com>
    Date:   Sat Nov 22 14:14:49 2025 +0200

      Implement convenience commands modus-themes-select-{dark,light}

     doc/modus-themes.info | 348 +++++++++++++++++++++++++++-----------------------
     doc/modus-themes.org  |  25 +++-
     modus-themes.el       |  54 ++++++--
     3 files changed, 250 insertions(+), 177 deletions(-)

0 files changed, 0 insertions, 0 deletions