Vocab document fixed

Hi there everyone,

Apparently I managed to mess up the vocab document at  
http://www.w3.org/1999/xhtml/vocab last time I edited it
(short version: I used the old version of Amaya which doesn't recognise  
RDFa, and which therefore deleted all the unknown attributes).

I have now repaired it, but I would be grateful if someone would  
double-check the triples.

Thanks.

Steven