[Xcb] documentation patches

[Michael Stapelberg]

Hello again,

Excerpts from Michael Stapelberg's message of 2012-03-26 16:40:53 +0200:
> Thanks for your comments. As you suggest, I would love to see my patches merged
> first, and then we can iterate based on that.
Now that the changes are merged (thanks Julien!), would you like me to address
your comments or do you want to send a patch yourself?

Best regards,
Michael