Method describe

tests/catch.hpp:2919–2933

                return true;
            }
            std::string describe() const override {
                std::string description;
                description.reserve( 4 + m_matchers.size()*32 );
                description += "( ";
                bool first = true;
                for( auto matcher : m_matchers ) {
                    if( first )
                        first = false;
                    else
                        description += " and ";
                    description += matcher->toString();
                }
                description += " )";
                return description;
            }

            MatchAllOf<ArgT>& operator && ( MatcherBase<ArgT> const& other ) {
                m_matchers.push_back( &other );