relative-pointer: Mention interaction with `wl_pointer.frame`
XWayland assumes relative motion events are followed by a frame
if
wl_pointer
has version 5 or greater:
https://gitlab.freedesktop.org/xorg/xserver/-/blob/master/hw/xwayland/xwayland-input.c
But the protocol didn't mention frame
. This may be implied, but
should be addressed specifically.
This should match existing implementations.