bug#30074: 26.0; Add function(s) for current monitor info

[Drew Adams <drew.adams@oracle.com>]

> > Please consider this bug report to be a
> > request for a function like [`current-monitor-size'].
> 
> Doesn't the returned monitor attributes list give you that information ?

Yes, and the bug report made that clear from the
beginning (with `display-monitor-attributes-list').

> (frame-monitor-attributes (selected-frame))
> => ((geometry 0 0 1920 1080)...)
> 
> What other information do you need ?

It's not about _needing other information_.
It's about having a function that gives you
the size info directly.

This is getting a bit ridiculous.  Why do
you think we have functions like this?

(defun frame-width (&optional frame)
  "Return number of columns available for display on FRAME.
If FRAME is omitted, describe the currently selected frame."
  (cdr (assq 'width (frame-parameters frame))))

Why don't you complain that `frame-parameters'
already gives you that information? "What other
information do you need?"