bug#64101: 29.0.91; Eglot inlay hints rendered out of order

[Eli Zaretskii]

> From: Milan Jovanovic <milanj@gmail.com>
> Date: Tue, 20 Jun 2023 15:34:42 +0200
> Cc: joaotavora@gmail.com, monnier@iro.umontreal.ca, 
>       kklimonda@syntaxhighlighted.com, 64101@debbugs.gnu.org
> 
> Well, from reading this thread I expected it to be sorted by priority.

They are, if they have different priorities and the same overlay
properties.

The problem was with the SECONDARY priority, since (according to
Stefan) the display code doesn't know about that feature.  I didn't
yet have time to look at that code.