Use SERIAL_ECHOLNPAIR for resend

Marlin/src/gcode/queue.cpp

@@ -268,8 +268,7 @@ void GCodeQueue::flush_and_request_resend(const serial_index_t serial_ind) {
     PORT_REDIRECT(SERIAL_PORTMASK(serial_ind));   // Reply to the serial port that sent the command
   #endif
   SERIAL_FLUSH();
-  SERIAL_ECHOPGM(STR_RESEND);
-  SERIAL_ECHOLN(serial_state[serial_ind.index].last_N + 1);
+  SERIAL_ECHOLNPAIR(STR_RESEND, serial_state[serial_ind.index].last_N + 1);
   SERIAL_ECHOLNPGM(STR_OK);
 }