bug#20815: 25.0.50; doc of `null'

[Eli Zaretskii]

> Date: Sun, 14 Jun 2015 15:31:46 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> 
> BTW, the URL for the online manual is not good for this node.
> 
> Following the convention, it should be simply
> http://www.gnu.org/software/emacs/manual/html_node/elisp/List-related-Predicates.html
> 
> But it is instead:
> http://www.gnu.org/software/emacs/manual/html_node/elisp/List_002drelated-Predicates.html
> 
> Somehow, the hyphen got translated to `_002d', unhelpfully.

Hex 2d is the codepoint of the hyphen.  Makeinfo converts all
punctuation characters like that, so the only hyphens left in the
node's name are those that were spaces before.

IOW, it's a feature.