bug#24520: 25.1.50; calccard.tex has somewhat unclear licensing

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Cc: 24520@debbugs.gnu.org,  naesten@gmail.com
> Date: Fri, 18 Nov 2016 02:28:41 -0500
> 
> Eli Zaretskii wrote:
> 
> >>    a) mention the filename "calccard.tex" so people receiving it
> >>       out-of-context can find the source easily
> >
> > The name of the file is already mentioned.
> 
> See 4af5981d

Thanks.

> BTW, the anchor http://www.gnu.org/software/emacs/#Manuals,
> cited in many refcards, doesn't exist any more.

How about updating that?