bug#51032: 29.0.50; Choices for blink-matching-paren

[Eli Zaretskii <eliz@gnu.org>]

> From: Arash Esbati <arash@gnu.org>
> Date: Tue, 05 Oct 2021 14:18:35 +0200
> 
> (defcustom blink-matching-paren t
>   "Non-nil means show matching open-paren when close-paren is inserted.
> If t, highlight the paren.  If `jump', briefly move cursor to its
> position.  If `jump-offscreen', move cursor there even if the
> position is off screen.  With any other non-nil value, the
> off-screen position of the opening paren will be shown in the
> echo area."
>   :type '(choice
>           (const :tag "Disable" nil)
>           (const :tag "Highlight" t)
>           (const :tag "Move cursor" jump)
>           (const :tag "Move cursor, even if off screen" jump-offscreen))
>   :group 'paren-blinking)
> 
> Is there a specific reason why users cannot choose this feature
> 
>     With any other non-nil value, the off-screen position of the opening
>     paren will be shown in the echo area.
> 
> via customize interface?

Obviously, because when the variable was made a defcustom, no one
bothered to include that, and no one did since then.

Patches welcome.