Update documentation

dune/contact/common/staticmgcontactproblem.hh

@@ -86,8 +86,7 @@ public:
   //! Return the i'th material
   MaterialType& getMaterial(size_t i) {return (*materials_)[i]; }
 
-
-  //! Set mass matrices which serve as a regularisation in case of pure Neumann problems
+  //! Set surface mass matrices in the case of Robin conditions
   void setMassMatrices(const std::vector<MatrixType>& mass)
   {
     mass_ = stackobject_to_shared_ptr<const std::vector<MatrixType> >(mass);