ENH: snappyHexMesh: update main snappyHexMeshDict. See #1031.

applications/utilities/mesh/generation/snappyHexMesh/snappyHexMeshDict

@@ -332,8 +332,11 @@ castellatedMeshControls
         //    // Optional directional expansion-ratio smoothing (after all
         //    // refinement). This will try to smooth out edge/cell size jumps
         //    // Specify smoothing direction and number of iterations
-        //    nSmoothExpansion    100;
         //    smoothDirection     (1 0 0);
+        //    // Smoothing of expansion ratio
+        //    nSmoothExpansion    100;
+        //    // Smoothing of positions
+        //    nSmoothPosition     100;
         //}
     }