bug#48307: Feature request: provide default keybindings to change the font size in all windows

[Clément Pit-Claudel]

On 5/10/21 3:35 PM, Gregory Heytings wrote:
> Here is the updated patch with, as discussed, a new user option to control 
> the frame resizing, and the additional C-x C-M-= binding.

Looks good!  A small stylistic comment:

+           (pcase key
+              ((or ?+ ?=) (* increment 5))
+              (?- (* (- increment) 5))
+              (?0 (- global-text-scale-adjust--default-height
+                     (face-attribute 'default :height)))
+              (_ (* increment 5)))))

Do you need the first branch?  If you remove it, those cases will be caught by 
the default fall-through.