Sketcher: fix knots PointPos coded as mid instead of start
Sketcher: fix knots PointPos coded as mid instead of start

Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master