bug#46853: Confusing terminology "face height" instead of "font size"

[Stefan Kangas <stefan@marxist.se>]

Severity: wishlist

I suggest changing the terminology "face height" to "font size" in user
documentation and messages.  For example, the documentation for
`text-scale-adjust' currently says:

   "Adjust the height of the default face by INC."

This is harder than it needs to be to understand, since the rest of the
world actually talks about "increase font size".  IOW, it would be more
clear if it said:

   "Adjust the font size in the current buffer by INC steps."

[This would also move talking about the `default' face further down, as
that is more of an implementation detail mostly of interest when
programming ELisp.]

Behind the scenes obviously a "face" is different from a "font" (as it
is rather a set of features that includes the font, formatting, etc.).
We should absolutely maintain that terminology.  We should also maintain
that if you want to customize the look of Emacs, including font size,
you need to customize this thing we call "faces".

As part of this, we could also consider introducing a new property for
`defface' called :size.  (Or :font-size and :font-scale which would
allow for semantics where we can specify :font-size 14 and mean 14pt
rather than 1.4pt.)