Optimize the time_vel_two_step function

[Ydaos]

Hello，
In the ruckig/postion_third_step1.cpp/
you can optimize the calculation formula for the second 'profile->t[3]' in the time_vel_two_step function

// Four step
    {
        profile->t[0] = 0;
        profile->t[1] = 0;
        profile->t[2] = a0/jMax;
        //profile->t[3] = (af_p3 - a0_p3)/(3*jMax_jMax*vMax) + (a0*v0 - af*vf + (af_af*h1 + a0_p3/jMax)/2)/(jMax*vMax) - (v0/vMax + 1.0)*a0/jMax - (vf/vMax + 1.0)*h1 + pd/vMax;
        profile->t[3] = (af_p3 - a0_p3)/(3*jMax_jMax*vMax) + (-a0*v0 - af*vf + (af_af*h1)/2)/(jMax*vMax) - (vf/vMax + 1.0)*h1 + pd/vMax;
        profile->t[4] = h1;
        profile->t[5] = 0;
        profile->t[6] = h1 + af/jMax;

        if (profile->check<ControlSigns::UDDU, ReachedLimits::VEL>(jMax, vMax, vMin, aMax, aMin)) {
            add_profile(profile);
            return;
        }
    }