bug#41026: Improve documentation of `makunbound' and `fmakunbound'

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Sat, 2 May 2020 15:53:37 +0200
> 
>  DEFUN ("makunbound", Fmakunbound, Smakunbound, 1, 1, 0,
> -       doc: /* Make SYMBOL's value be void.
> -Return SYMBOL.  */)
> +       doc: /* Make variable SYMBOL's value be void.
> +Return SYMBOL.
> +
> +For more information, see Info node `(elisp) Void Variables'.
> +
> +The corresponding operation for functions is `fmakunbound'.  */)
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The "corresponding" part isn't accurate, is it?

Thanks.