message: Fix link to reference code
  Previous link to reference VTK implementation has an orientation bug
diff: @@ -8741,7 +8741,7 @@ int VTKTriangleDOFOffset(int ref, int i, int j)
  int CartesianToVTKPrism(int i, int j, int k, int ref)
  {
  - // Cf. https://git.io/JvW4P
  + // Cf. https://git.io/JvW0M
  int om1 = ref - 1;
  int ibdr = (i == 0);
  int jbdr = (j == 0);
  