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

src/Mod/Fem/App/PropertyPostDataObject.cpp

@@ -70,8 +70,8 @@ void PropertyPostDataObject::scaleDataObject(vtkDataObject *dataObject, double s
         for (vtkIdType i = 0; i < points->GetNumberOfPoints(); i++) {
             double xyz[3];
             points->GetPoint(i, xyz);
-            for (int j = 0; j < 3; j++)
-                xyz[j] *= s;
+            for (double & j : xyz)
+                j *= s;
             points->SetPoint(i, xyz);
         }
     };