not straight ledge fixup

// by daemonicky
if (grab_can)
...
    // handle slopes
    nudge_up = '0 0 0';
    while (nudge_up_z < 5)
    {
        if (PlayerCanGrabAround(self.origin + nudge_up, _radius/*hack*/,  4 * 4))
        {
            setorigin(self, self.origin+nudge_up);
            grab_z += nudge_up_z;
            break;
        }
        nudge_up_z += 0.6;//0.5;
    }
    bprint(vtos(nudge_up));
    bprint("\n");

    if (PlayerCanGrab(_radius/*hack*/))
...