Graphical LCD note

Marlin/Configuration.h

@@ -1928,6 +1928,8 @@
 // IMPORTANT: The U8glib library is required for Graphical Display!
 //            https://github.com/olikraus/U8glib_Arduino
 //
+// NOTE: If the LCD is unresponsive you may need to reverse the plugs.
+//
 
 //
 // RepRapDiscount FULL GRAPHIC Smart Controller