message: clarify what UseMFEMMassLinearSolver and UseSundialsMassLinearSolver attach
diff: @@ -291,14 +291,22 @@ public:
  /// Attach a SUNDIALS GMRES linear solver to ARKode.
  void UseSundialsLinearSolver();
  - /// Attach an MFEM mass matrix linear solver to ARKode.
  - /** @param[in] tdep An integer flag indicating if the mass matrix is time
  - dependent (1) or time independent (0) */
  + /** @brief Attach mass matrix linear system setup, solve, and matrix-vector
  + product methods from the TimeDependentOperator i.e., SUNMassSetup(),
  + SUNMassSolve(), and SUNMassMult() to ARKode.
  +
  + @param[in] tdep An integer flag indicating if the mass matrix is time
  + dependent (1) or time independent (0)
  + */
  void UseMFEMMassLinearSolver(int tdep);
  - /// Attach a SUNDIALS mass matrix linear solver to ARKode.
  - /** @param[in] tdep An integer flag indicating if the mass matrix is time
  - dependent (1) or time independent (0) */
  + /** @brief Attach the SUNDIALS GMRES linear solver and the mass matrix
  + matrix-vector product method from the TimeDependentOperator i.e.,
  + SUNMassMult() to ARKode to solve mass matrix systems.
  +
  + @param[in] tdep An integer flag indicating if the mass matrix is time
  + dependent (1) or time independent (0)
  + */
  void UseSundialsMassLinearSolver(int tdep);
  /// Select the ARKode step mode: ARK_NORMAL (default) or ARK_ONE_STEP.
  