Update documentation for pre-patched LocalSolvers.

Point out the regularization in particular for all local solvers.

dune/solvers/iterationsteps/blockgssteps.hh

@@ -240,8 +240,9 @@ auto diagRegularize(double p, LocalSolver&& localSolver) {
 
 } // end namespace LocalSolverRegularizer
 
-//! \brief is @LinearSolvers::direct with ignore nodes.
-//! \param r Regularization parameter. Set to 0.0 to switch off regularization.
+//! \brief is @LinearSolvers::direct with ignore nodes and regularization.
+//! \param r Regularization parameter. Set to 0.0 (default value) 
+//!        to switch off regularization.
 struct Direct {
   Direct(double r = LocalSolverRegularizer::defaultDiagRegularizeParameter)
       : r_(r) {}
@@ -265,7 +266,9 @@ auto direct(Args&&... args) {
   return Direct(std::forward<Args>(args)...);
 }
 
-//! \brief is @LinearSolvers::ldlt with ignore nodes.
+//! \brief is @LinearSolvers::ldlt with ignore nodes and regularization.
+//! \param r Regularization parameter. Set to 0.0 (default value) 
+//!        to switch off regularization.
 struct LDLt {
   LDLt(double r = LocalSolverRegularizer::defaultDiagRegularizeParameter)
       : r_(r) {}
@@ -289,7 +292,9 @@ auto ldlt(Args&&... args) {
   return LDLt(std::forward<Args>(args)...);
 }
 
-//! \brief is @LinearSolvers::cg with ignore nodes.
+//! \brief is @LinearSolvers::cg with ignore nodes and regularization.
+//! \param r Regularization parameter. Set to 0.0 (default value) 
+//!        to switch off regularization.
 struct CG {
   CG(size_t maxIter = LinearSolvers::defaultCgMaxIter,
      double tol = LinearSolvers::defaultCgTol,
@@ -319,6 +324,9 @@ auto cg(Args&&... args) {
   return CG(std::forward<Args>(args)...);
 }
 
+//! \brief is @LinearSolvers::gs with ignore nodes and regularization.
+//! \param r Regularization parameter. Set to 0.0 (default value) 
+//!        to switch off regularization.
 struct GS {
   GS(double tol = LinearSolvers::defaultGsTol,
      double r = LocalSolverRegularizer::defaultDiagRegularizeParameter)