bug#56820: outline-minor-mode replacing the first character with an arrow

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: yilkalargawworkneh@gmail.com,  larsi@gnus.org,  56820@debbugs.gnu.org
> Date: Wed, 07 Sep 2022 21:36:06 +0300
> 
> So the column for outline indicators could be implemented the same way
> as display-line-numbers-mode.

Yes, that's a possibility.

> Excuse my ignorance, is display-line-numbers-mode implemented by
> using margins?

No.  We simply usurp a few columns from the text area, on the layout
level of the display engine.