bug#57813: Icon images are non-functional

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: 57813@debbugs.gnu.org
> Date: Mon, 19 Sep 2022 22:37:08 +0300
> 
> >> Then the right margin could be used with:
> >
> > Thanks, the code LGTM.
> 
> Pushed.  There is still a remaining problem: mouse clicks in the margins
> have no effect.  Then I noticed in (info "(elisp) Display Margins"):
> 
>   There is currently no way to make text or images in the margin
>   mouse-sensitive.
> 
> This means no way to bind mouse events in the margins?

When I click the mouse in a left margin, "C-h c" says:

  <left-margin> <mouse-1> (translated from <down-mouse-1> <mouse-1>) at that 
spot is undefined

So it looks like this is possible, and that text in the manual is
simply outdated?