bug#30659: Only local map define-key examples

[Eli Zaretskii]

> From: 積丹尼 Dan Jacobson
>       <jidanni@jidanni.org>
> Date: Thu, 01 Mar 2018 04:13:16 +0800
> 
> At the end of (info "(emacs) Init Rebinding")
> there is an example,
> 
>      (add-hook 'texinfo-mode-hook
>                (lambda ()
>                  (define-key texinfo-mode-map "\C-cp"
>                              'backward-paragraph)
>                  (define-key texinfo-mode-map "\C-cn"
>                              'forward-paragraph)))
> 
> 
> Please add to this example also an example of undefining an existing key.
> Else users will use local-unset-key that they find on (info "(emacs) 
> Rebinding"),
> which may or may not be correct.

I'm not sure I understand what's wrong with local-unset-key.  (And
"Rebinding" also mentions global-unset-key, btw.)