message: Fix missing new line when ASCII protocol is used with checksums.
  See
diff: @@ -53,7 +53,7 @@ void AsciiProtocol::respond(bool include_checksum, const char * fmt, TArgs&& ...
  uint8_t checksum = 0;
  for (size_t i = 0; i < len; ++i)
  checksum ^= tx_buf[i];
  - len += snprintf(tx_buf + len, sizeof(tx_buf) - len, "*%u", checksum);
  + len += snprintf(tx_buf + len, sizeof(tx_buf) - len, "*%u\r\n", checksum);
  } else {
  len += snprintf(tx_buf + len, sizeof(tx_buf) - len, "\r\n");
  }
  