protocol: Clarify pointer axis event
protocol: Clarify pointer axis event

Pointer axis events are in the same coordinate space as motion events.

Signed-off-by: Jonas Ådahl <67dcd8a17e758192e0cbb577ce1d62cc7da6cf49@gmail.com>

sir-murray/wayland,bitfactor/wayland,sir-murray/wayland,abooij/wayland,mchalupa/wayland,bitfactor/wayland,abooij/wayland,bitfactor/wayland,eyolfson/wayland,mchalupa/wayland,eyolfson/wayland,abooij/wayland,tulcod/wayland,tulcod/wayland,mchalupa/wayland,tulcod/wayland,eyolfson/wayland,sir-murray/wayland