bug#74423: Low level key events

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 13 Dec 2024 23:55:18 +0100
> Cc: luangruo@yahoo.com, 74423@debbugs.gnu.org, monnier@iro.umontreal.ca
> From: Cecilio Pardo <cpardo@imayhem.com>
> 
> This new version includes a manual entry, and corrected doc strings and 
> comments.

Thanks, a few minor comments.

> +@cindex @code{low-level-key} event
> +@item (low-level-key @var{is-key-press} @var{key} @var{modifier} @var{time} @var{frame})
> +This event is sent on the physical press or release of keys, only on GUI
> +systems, currently X, MS-Windows and PGTK.

Aren't these events sent only if enable-low-level-key-events is
non-nil?  If so, this should be documented, and the variable itself
should be documented.

> +@var{is-key-press} is @code{t} for a key press, @code{nil} for a key release.
> +@var{time} is the event's time in milliseconds, @var{frame} is the
> +frame receiving it. @var{modifier} is @code{nil} if the key is not a
                     ^^
Two spaces between sentences.

> +  DEFVAR_LISP ("enable-low-level-key-events", Venable_low_level_key_events,
> +	       doc: /* If non-nil, reception of low-level key events is enabled.
> +
> +The value configures the set of keys that are handled:
> +
> +If t, send events for all keys.
> +
> +If a number, send events for the corresponding keysym.  When calling
> +'llk-init', a set of variables with the xk- prefix is initialized with
   ^^^^^^^^^^
In doc strings, we quote symbols `like this'.