s42c current setting via uart

[frollard]

per the manual: 0 1 2 3 should correspond to low med high vhigh

When setting via the menu on oled, setting to low causes uart to respond mode 3, medium 2, high 1, vhigh 0. velocity on demand position matches what the oled reads = vhigh(0) = fastest, low(3)= slowest.

Not sure if it is backwards in the documentation or code.