bug#81441: [PATCH] Have 'toggle-rot13-mode' behave buffer locally

> From: Philip Kaludercic <[email protected]>
> Cc: [email protected]
> Date: Sun, 09 Aug 2026 09:23:11 +0000
> 
> Eli Zaretskii <[email protected]> writes:
> 
> > Sorry, I don't understand.  You mean to have a minor mode (which by
> > definition is per-buffer) in addition to the command, which will stay
> > per-window?  
> 
> Yes, so basically just add
> 
>  (define-minor-mode rot13-buffer-mode
>    "Toggle the use of ROT13 encoding for the current buffer."
>    :global nil
>    (setq buffer-display-table (and rot13-buffer-mode
>                                    rot13-display-table)))
> 
> to the file.

I won't object, but let's update the doc strings so that both
alternatives mention the other one.