Issue #4473: Expose openCommand() CommandConstraints.cpp to translation
Issue #4473: Expose openCommand() CommandConstraints.cpp to translation

`Sketcher/Gui/CommandConstraints.cpp` will now be parsed for translation. Based on https://github.com/FreeCAD/FreeCAD/pull/3993#issuecomment-715906238  
( ref. Issue #4473 )
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