Function convertUnknownEnumToString

CvPlot/ext/catch2/inc/catch.hpp:1626–1628

        template<typename E>
        std::string convertUnknownEnumToString( E e ) {
            return ::Catch::Detail::stringify(static_cast<typename std::underlying_type<E>::type>(e));
        }

#if defined(_MANAGED)
        template <typename T>