XKB: Rewrite AXOption
XKB: Rewrite AXOption

AXOption can be an <enum> instead of a <union>, which is a much simpler
construct.

Signed-off-by: Peter Harris <859d2524afe9d1b926cf5c02089ad1cbab640cc0@opentext.com>
Reviewed-By: Ran Benita <03686f031484546e32da38cdd36b1b8bb5e2be3c@gmail.com>

nbaum/xcb-proto,nbaum/xcb-proto