bug#71282: 30.0.50; hl-line overlay priority has no affect

[Eli Zaretskii <eliz@gnu.org>]

> From: João Távora <joaotavora@gmail.com>
> Date: Sun, 30 Jun 2024 16:50:32 +0100
> Cc: mohkale@kisara.moe, stefankangas@gmail.com, 71282@debbugs.gnu.org
> 
> On Sun, Jun 30, 2024 at 4:34 PM Eli Zaretskii <eliz@gnu.org> wrote:
> 
> > The mechanism exists: find the face of the buffer text, and use it (or
> > some of its attributes, like background color) in determining the face
> > of the overlay string.
> 
> Then if that mechanism doesn't require anything specific of package X or
> Y, it should be possible to condense in a function (that shouldn't live in
> Eglot, but OK it it starts life there, I guess) that takes a face with
> a number of
> attributes,merges with whatever is "the face of the buffer text" and return
> an (anonymous) face.  If so, then that "mistery" function is the fix
> to this issue.

Patches welcome.