Comment for RADDS + RRDFGSC

Marlin/src/pins/pins_RADDS.h

 
   #elif ENABLED(REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER)
 
+    // The REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER requires
+    // an adapter such as https://www.thingiverse.com/thing:1740725
+
     #define LCD_PINS_RS     42
     #define LCD_PINS_ENABLE 43
     #define LCD_PINS_D4     44