bug#57970: 29.0.50; Create new defgroup for pixel-scroll.el

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: stefankangas@gmail.com,  larsi@gnus.org,  57970@debbugs.gnu.org
> Date: Mon, 11 Sep 2023 22:46:03 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > This particular discussion is about two modes that have very similar
> > names.  I think explaining the strengths and weaknesses (even if they
> > are minor and can be overcome, given enough efforts) goes at least
> > some way towards resolving user confusion about these two, and
> > changing the name, even if not 110% accurate, is even better.
> 
> Users customarily search for terms in the vein of "pixel scroll", which
> that must still be taken into account: whatever name we select for the
> mode should incorporate the word "pixel".
> 
> One more data point: within the stream of feature requests that
> constitued the impetus for my decision to implement this feature, not a
> single request mentioned the word "touchpad", whereas "pixel" and
> "precise" abounded.  At least in my recollection.

We could use touchpad-pixel-scroll, for example.