Fix serial debug ouput

Marlin/src/gcode/control/M111.cpp

     SERIAL_ECHOPGM(MSG_DEBUG_OFF);
     #if !defined(__AVR__) || !defined(USBCON)
       #if ENABLED(SERIAL_STATS_RX_BUFFER_OVERRUNS)
-        SERIAL_ECHOLNPAIR("Buffer Overruns: ", customizedSerial.buffer_overruns());
+        SERIAL_ECHOPAIR("\nBuffer Overruns: ", customizedSerial.buffer_overruns());
       #endif
 
       #if ENABLED(SERIAL_STATS_RX_FRAMING_ERRORS)
-        SERIAL_ECHOLNPAIR("Framing Errors: ", customizedSerial.framing_errors());
+        SERIAL_ECHOPAIR("\nFraming Errors: ", customizedSerial.framing_errors());
       #endif
 
       #if ENABLED(SERIAL_STATS_DROPPED_RX)
-        SERIAL_ECHOLNPAIR("Dropped bytes: ", customizedSerial.dropped());
+        SERIAL_ECHOPAIR("\nDropped bytes: ", customizedSerial.dropped());
       #endif
 
       #if ENABLED(SERIAL_STATS_MAX_RX_QUEUED)
-        SERIAL_ECHOLNPAIR("Max RX Queue Size: ", customizedSerial.rxMaxEnqueued());
+        SERIAL_ECHOPAIR("\nMax RX Queue Size: ", customizedSerial.rxMaxEnqueued());
       #endif
     #endif //  !defined(__AVR__) || !defined(USBCON)
   }