bug#61812: 30.0.50; Eglot inlay hints "pile up"

[Eli Zaretskii <eliz@gnu.org>]

> From: Chinmay Dalal <dalal.chinmay.0101@gmail.com>
> Cc: 61812@debbugs.gnu.org
> Date: Sun, 26 Feb 2023 19:20:04 +0530
> 
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: Chinmay Dalal <dalal.chinmay.0101@gmail.com>
> >> Cc: 61812@debbugs.gnu.org
> >> Date: Sun, 26 Feb 2023 18:29:35 +0530
> >> 
> >> > And if the latter, what exactly
> >> > causes the duplicates?  You say "scroll around", but how do you
> >> > "scroll around" (with what commands), and can you try figuring out
> >> > what exactly triggers the appearance of the duplicates?
> >> 
> >> "Scroll around" was inaccurate, apologies. I meant using C-n/C-p to move
> >> the cursor.
> >
> > So if you move through a region with C-n/C-p time and again, you will
> > see the duplicates appear one by one?
> 
> Yes, this is not deterministic though - some places have duplicates,
> some don't
> 
> > If you go to the place where the duplicate hints are shown and type
> > "M-x describe-text-properties RET", how many overlays are shown in the
> > window Emacs pops up?  Do you see a separate overlay for each
> > duplication?
> 
> Yes, there are separate overlays for each duplication, for example:
> 
>  From 7070 to 7070
>   before-string        [Show]
>   eglot--inlay-hint    t
>   eglot--overlay       t
>  From 7070 to 7070
>   before-string        [Show]
>   eglot--inlay-hint    t
>   eglot--overlay       t

So it sounds like we are not deleting old overlays before adding new
ones.

Or maybe we should delete them automatically when point moves far
enough?