message: Update miniapps/meshing/twist.cpp
  Expanding description in comment block
diff: // terms of the BSD-3 license. We welcome feedback and contributions, see file
  // CONTRIBUTING.md for details.
  //
  -// ----------------------------------------------
  -// Twist Miniapp: Generate simple twisted meshes
  -// ----------------------------------------------
  +// -------------------------------------------------------
  +// Twist Miniapp: Generate simple twisted periodic meshes
  +// -------------------------------------------------------
  //
  // This miniapp generates simple periodic meshes to demonstrate MFEM's handling
  // of periodic domains. MFEM's strategy is to use a discontinuous vector field
  