docs: add cairocffi.xcb to mock modules
docs: add cairocffi.xcb to mock modules

Signed-off-by: Tycho Andersen <6b523322678240882acbb4da5312a12d8cd0082d@tycho.ws>

qtile/qtile,ramnes/qtile,qtile/qtile,ramnes/qtile,tych0/qtile,tych0/qtile