bug#51847: Minor Refcard fix.

[Eli Zaretskii]

> From: André A. Gomes <andremegafone@gmail.com>
> Cc: 51847@debbugs.gnu.org
> Date: Sun, 14 Nov 2021 18:35:51 +0300
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> As stated in the commit message, it's easier to type C-0 C-k than M-0
> >> C-k.  
> >> 
> >> Mickey Peterson in his book "Mastering Emacs", calls such a thing
> >> "maintaining the tempo".  For example, "C-- M-d" and "M-- M-d" are
> >> equivalent, but the latter is much easier to type.  The former is said
> >> to "break the tempo".
> >
> > But M-0 has the advantage of being available on text-mode frames,
> > whereas C-0 requires a GUI frame.  That's why the refcards use the
> > former.
> 
> I see.  I wasn't aware of that.
> 
> Still, I'd say that "C-u 0 C-k" is saner than "M-0 C-k".  WDYT?

I don't know.  Does anyone else have an opinion?