add some acceleration-related info to the man page
add some acceleration-related info to the man page

Signed-off-by: Simon Thum <0944885fc79f6a208c69efde4322182deb863f28@gmx.de>
Signed-off-by: Peter Hutterer <b9c50af7afa7642f6f854434cda9ffe54ece8b85@who-t.net>

mad-s/xf86-input-synaptics-absolute,mad-s/xf86-input-synaptics-absolute