message: Update Mesh::MakePeriodic Doxygen
diff: @@ -583,7 +583,10 @@ public:
  /** Each vertex @a i will be mapped to vertex @a v2v[i], such that all
  vertices that are coincident under the periodic mapping get mapped to
  the same index. The mapping @a v2v can be generated from translation
  - vectors using Mesh::CreatePeriodicVertexMapping. */
  + vectors using Mesh::CreatePeriodicVertexMapping.
  + @note MFEM requires that each edge of the resulting mesh be uniquely
  + identifiable by a pair of unique vertiecs. As a consequence, periodic
  + boundaries must be connected by at least three edges. */
  static Mesh MakePeriodic(const Mesh &orig_mesh, const std::vector<int> &v2v);
  ///@}
  