[Xcb] XCB documentation effort

[Michael Stapelberg]

Hi Peter,

Excerpts from Peter Harris's message of 2011-11-24 23:36:54 +0000:
> Input on this issue is very welcome.
Alright, I guess I’ll implement the short-term solution :). This also helps
bindings for other languages, for example the X11::XCB Perl bindings.

> The names in function parameters are documentation only. Changing the
> names affects neither API nor ABI AFAIK, so the change should be okay. I
> think I'd be a smidgen happier if the man pages match the .h files, but
> I can't bring myself to care all that much.
OK, so I’ll use 'conn' in the documentation. To make you happy, I am also
willing to change it in the C generator (separate patch of course). Do you
agree? :)

Best regards,
Michael