[Rd] Links to non-vignette documentation

[hadley wickham]

> We were referring to an HTML index file.  If you want to have a
> reference from your package man page (foo-package.Rd) or some other man
> page, you can use \url{../doc/my.pdf} and the link will work in HTML
> versions of help, and won't be too misleading in other versions
> (especially if you explain how to use it).

Ok, I'll give that a go.

> I don't think you can do that, but you should be using a package man
> page anyway.

Can you suggest a good example of a package man page?  I've tried a
few packages and haven't been able to find one.  The example generated
by promptPackage suggests I need to duplicate the contents of
DESCRIPTION and INDEX.

Hadley