bug#57813: Icon images are non-functional

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: 57813@debbugs.gnu.org
> Date: Sat, 17 Sep 2022 22:37:22 +0300
> 
> Here is a preliminary patch, but using buffer-local left-margin-width
> exhibits strange behavior: margins don't always appear immediately
> after switching the buffer.

Margins are specific to a window, not to a buffer.  See the
description of set-window-margins in the ELisp manual, and the
accompanying description of set-window-buffer there.