bug#59122: 29.0.50; global-text-scale-adjust not working

[Eli Zaretskii]

> Cc: 59122@debbugs.gnu.org, Rudolf Adamkovič <salutis@me.com>
> From: Stefan Kangas <stefankangas@gmail.com>
> Date: Wed, 9 Nov 2022 14:28:54 +0100
> 
> I can reproduce this bug on macOS 12.6.1 (OP is on 12.6).
> 
> After pressing '+', '-' still doesn't decrease the font size.  I can
> only increase it using '+'.

Please step with Edebug into global-text-scale-adjust, and tell what
do you see in the variable 'key' in the following fragment from the
command:

    (let* ((key (event-basic-type last-command-event))
           (echo-keystrokes nil)
           (cur (face-attribute 'default :height))
           (inc
            (pcase key
              (?- (* (- increment) 5))
              (?0 (- global-text-scale-adjust--default-height cur))
              (_ (* increment 5))))