message: Extend a little some of the doxygen comments related to the
  struct Mesh::FaceInformation.
diff: @@ -1291,20 +1291,20 @@ public:
  enum class ElementConformity { Coincident, Superset, Subset, NA };
  /** This enumerated type describes the corresponding FaceInfo internal
  - representation and encryption cases, c.f. FaceInfo's documentation:
  + representation (encoded cases), c.f. FaceInfo's documentation:
  Classification of a local (non-ghost) face based on its FaceInfo:
  - Elem2No >= 0 --> local interior face; can be either:
  - NCFace == -1 --> LocalConformingInterior,
  - - NCFace >= 0 --> LocalNonconformingInterior,
  + - NCFace >= 0 --> LocalNonconformingInterior (nonconforming slave),
  - Elem2No < 0 --> local "boundary" face; can be one of:
  - NCFace == -1 --> conforming face; can be either:
  - Elem2Inf < 0 --> TrueBoundary,
  - Elem2Inf >= 0 --> SharedConformingInterior,
  - NCFace >= 0 --> nonconforming face; can be one of:
  - - Elem2Inf < 0 --> MasterNonconforming,
  - - Elem2Inf >= 0 --> SlaveNonconforming.
  + - Elem2Inf < 0 --> MasterNonconforming (shared or not shared),
  + - Elem2Inf >= 0 --> SlaveNonconforming (shared).
  Classification of a ghost (non-local) face based on its FaceInfo:
  - - Elem1No == -1 --> GhostMaster,
  + - Elem1No == -1 --> GhostMaster (includes other unused ghost faces),
  - Elem1No >= 0 --> GhostSlave.
  */
  enum class FaceInfoTag { LocalConformingInterior,
  @@ -1345,20 +1345,23 @@ public:
  int ncface;
  const DenseMatrix* point_matrix;
  - /// @brief Return true if the face is a local interior face.
  + /** @brief Return true if the face is a local interior face which is NOT
  + a master nonconforming face. */
  bool IsLocal() const
  {
  return element[1].location == Mesh::ElementLocation::Local;
  }
  - /// @brief Return true if the face is a shared interior face.
  + /** @brief Return true if the face is a shared interior face which is NOT
  + a master nonconforming face. */
  bool IsShared() const
  {
  return element[1].location == Mesh::ElementLocation::FaceNbr;
  }
  /** @brief return true if the face is an interior face to the computaion
  - domain, either a local or shared interior face (not a boundary face).
  + domain, either a local or shared interior face (not a boundary face)
  + which is NOT a master nonconforming face.
  */
  bool IsInterior() const
  {
  @@ -1401,6 +1404,9 @@ public:
  }
  /// @brief Return true if the face is a nonconforming coarse face.
  + /** Note that ghost nonconforming master faces cannot be clearly
  + identified as such with the currently available information, so this
  + method will return false for such faces. */
  bool IsNonconformingCoarse() const
  {
  return topology == FaceTopology::Nonconforming &&
  