protocol: add the wl_pointer.axis_v120 events

These events are for high-resolution wheels. Each logical wheel click
represents an axis v120 value of 120, fractions of a wheel click an
integer fraction thereof. The new event replaces
wl_pointer.axis_discrete for wl_pointer versions 8 and above.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
2 jobs for wip/hi-res-scrolling in 1 minute and 51 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Build
passed #2733200
build-native-autotools

00:01:51

passed #2733201
build-native-meson

00:00:51