bug#32212: 26; `subword-mode' doc string shows empty key-binding list

[Eli Zaretskii]

> From: Noam Postavsky <npostavs@gmail.com>
> Date: Thu, 19 Jul 2018 20:58:52 -0400
> Cc: 32212@debbugs.gnu.org
> 
> > emacs -Q
> >
> > C-h f subword-mode
> >
> > You see this at the end of buffer *Help*:
> >
> > key             binding
> > ---             -------
> >
> >
> > It's not just about this appearing before the library is loaded.
> > Loading the library does not populate the list of keys and their
> > bindings.  You always get such a heading, with no keys shown.
> 
> 
> Seems to be a regression in 25.1, in 24.5 I see
> 
> key             binding
> ---             -------
> 
> <remap>        Prefix Command
> 
> <remap> <backward-kill-word>    subword-backward-kill

ISTR that the implementation changed radically, so perhaps this is the
(unintended) consequence.