bug#65578: Eglot with mouse

[Juri Linkov]

>> xref-find-definitions-at-mouse uses save-excursion with
>> mouse-set-point before calling xref-backend-identifier-at-point.
>> But the same save-excursion with mouse-set-point can't be added
>> around xref-find-definitions because save-excursion will restore
>> the original position after visiting the found identifier.
>
> Could we do that without additional save-excursion?
>
> diff --git a/lisp/progmodes/xref.el b/lisp/progmodes/xref.el
> index 0666b18cba1..0c3e34fe0a5 100644
> --- a/lisp/progmodes/xref.el
> +++ b/lisp/progmodes/xref.el
> @@ -1637,7 +1637,9 @@ xref-find-definitions-at-mouse
>             (mouse-set-point event)
>             (xref-backend-identifier-at-point (xref-find-backend)))))
>      (if identifier
> -        (xref-find-definitions identifier)
> +        (progn
> +          (mouse-set-point event)
> +          (xref-find-definitions identifier))
>        (user-error "No identifier here"))))

The problem with this solution is that when it doesn't find
the identifier then it leaves point at the wrong place.