[!354] [prec] Fix typo in error message

Merge branch 'fix/prec-typo' into 'master'

See merge request [core/dune-istl!354]

  [core/dune-istl!354]: Nonecore/dune-istl/merge_requests/354

dune/istl/preconditioners.hh

@@ -92,7 +92,7 @@ namespace Dune {
     : inverse_operator_(inverse_operator)
     {
       if(c != -1 && SolverCategory::category(inverse_operator_) != c)
-        DUNE_THROW(InvalidStateException, "User supplied solver category does not match that of the supplied iverser operator");
+        DUNE_THROW(InvalidStateException, "User-supplied solver category does not match that of the given inverse operator");
     }
 
     virtual void pre(domain_type&,range_type&)