tutorials: Updated formatting of dictionaries and specification of 'plane' and 'samplePlane'

tutorials/mesh/foamyQuadMesh/square/system/surfaceFeatureExtractDict

@@ -30,7 +30,7 @@ unit_cube.stl
     subsetFeatures
     {
         // Use a plane to select feature edges
-        // (normal)(basePoint)
+        // (normal)(point)
         // Keep only edges that intersect the plane will be included
         plane               (0 0 1)(0 0 0);