bug#31682: for to tags/emacs-26.2: Add NS style text scale keybindings

[Eli Zaretskii]

> Date: Sat, 02 Jun 2018 02:45:28 -0400
> From: Van L <van@scratchspace.com.au>
> 
> Alan Third writes:
> 
> > >     ;;
> > >     ;; Allow Command-Plus-or-Minus to text-scale fontsize.
> > >     ;;
> 
> > I’ve attached a patch for this.
> 
> I've re-created the patch based on tags/emacs-26.1 for to 26.2.

But this is not a bug, is it?  If not, it should go to master, not the
emacs-26 branch.

Thanks.