message: Fix doxygen warnings: use 'petsc::Vec' and 'petsc::Mat'
  instead of 'Vec' and 'Mat' where needed for doxygen.
diff: @@ -287,7 +287,7 @@ PetscParVector::PetscParVector(const PetscParMatrix &A,
  _SetDataAndSize_();
  }
  -PetscParVector::PetscParVector(Vec y, bool ref) : Vector()
  +PetscParVector::PetscParVector(petsc::Vec y, bool ref) : Vector()
  {
  if (ref)
  {
  @@ -1244,7 +1244,7 @@ void PetscParMatrix::Destroy()
  X = Y = NULL;
  }
  -PetscParMatrix::PetscParMatrix(Mat a, bool ref)
  +PetscParMatrix::PetscParMatrix(petsc::Mat a, bool ref)
  {
  if (ref)
  {
  