bug#12924: 24.3.50; Request: Provide a command to show the node in the manual where avariable is described

[Drew Adams]

> Provide a command `Info-goto-emacs-variable-node', bound to `C-h V',
> that be to variables as `Info-goto-emacs-command-node' (bound to `C-h
> F') is to commands.
> 
> That is: `C-h V search-whitespace-regexp' would take me to the info
> node "(emacs) Special Isearch", where this variable is explained.
> 
> This would be a useful feature, and would fit quite well in the
> current scheme of help commands (`C-h f/F' for commands; `C-h k/K' for
> keys; and now `C-h v/V' for variables).

See also:

http://lists.gnu.org/archive/html/emacs-devel/2011-06/msg00368.html

http://www.emacswiki.org/cgi-bin/wiki/HelpPlus#toc1