bug#59719: 29.0.60; emacs-news-mode does not adjust the width of the fringe to accommodate the outline icons

[Juri Linkov]

>> This is a known limitation of the margin area: its width is limited
>> to 10 pixels.
>
> ??? The width of the display margin can be controlled by set-window-margins.

set-window-margins specifies the number of characters.  Maybe need to
set the margin width to more characters if string-width returns more
than 1 character?

But the core problem is that when font size is increased in the buffer,
the margin pixel size doesn't increase proportionally.