The z_adjust offset provided to adjust_steppers is calculated given the
steppers adjust exactly according to the given x_adjust/y_adjust. As the
algorithm eliminates an offset that is common to all steppers, this offset
must be taken into account in the final correction.
Signed-off-by: Arne Jansen <arne@die-jansens.de>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>