[CSSWG][css3-namespace] Updated REC of CSS Namespaces

The CSS WG has published an updated Working Draft of the CSS Namespaces module

     http://www.w3.org/TR/css3-namespace/

This is just an update to add some conveniently pre-composed grammar constructs
for other specs to refer to: in addition to qname_prefix and wqname_prefix,
we now have qname, wqname, and wqwname. Unless you're editing a spec that relies
on CSS Namespaces, feel free to ignore this announcement. :)

For the CSSWG,
fantasai