bug#37848: 27.0.50; hl-line and line-numbers out of sync

[Eli Zaretskii]

> From: Andrey Orst <andreyorst@gmail.com>
> Date: Mon, 21 Oct 2019 13:24:11 +0300
> Cc: 37848@debbugs.gnu.org
> 
> > The line-number display has nothing to do with this, it works
> > correctly in this case.
> 
> It may work correctly, but I the issue is with the fact that line
> number and hl-line are out of sync.

More accurately, hl-line's overlay is out of sync with the window-point.

> Can I prevent this?

It's a bug in hl-line that needs to be fixed.

The display engine runs pre-redisplay-function for the window in this
case, so perhaps hl-line could install its hook there and fix its
overlay when it is called.

Patches are welcome.