FEM: modernize C++: use range-based for loop

src/Mod/Fem/Gui/ViewProviderFemConstraintContact.cpp

@@ -114,9 +114,9 @@ void ViewProviderFemConstraintContact::updateData(const App::Property* prop)
         // Points and Normals are always updated together
         Gui::coinRemoveAllChildren(pShapeSep);
 
-        for (std::vector<Base::Vector3d>::const_iterator p = points.begin(); p != points.end(); p++) {
+        for (const auto & point : points) {
             //Define base and normal directions
-            SbVec3f base(p->x, p->y, p->z);
+            SbVec3f base(point.x, point.y, point.z);
             SbVec3f dir(n->x, n->y, n->z);//normal
 
             ///Visual indication