Method operator|=

extlibs/catch/include/catch/catch.hpp:9178–9181

        std::vector<Arg> m_args;

        auto operator|=( ExeName const &exeName ) -> Parser & {
            m_exeName = exeName;
            return *this;
        }

        auto operator|=( Arg const &arg ) -> Parser & {
            m_args.push_back(arg);