Update endpoint_impl.hpp

template <typename connection, typename config>
void endpoint<connection,config>::close(connection_hdl hdl, 
    const close::status::value code, const std::string & reason)
{
    lib::error_code ec;
    send(hdl,code,reason,ec);
~~~~~~~~ I think this is a mistyping of 'close'
    if (ec) { throw ec; }
}