typos and Due compliants comments on Keyboard examples

Author: Fede85

build/shared/examples/09.USB/Keyboard/KeyboardMessage/KeyboardMessage.ino

@@ -6,8 +6,9 @@
  Sends a text string when a button is pressed.
  
  The circuit:
- * pushbutton attached from pin 2 to +5V
- * 10-kilohm resistor attached from pin 4 to ground
+ * pushbutton attached from pin 2 to +5V on AVR boards 
+   and to +3.3V to the Arduino Due
+ * 10-kilohm resistor attached from pin 2 to ground
  
  created 24 Oct 2011
  modified 27 Mar 2012

build/shared/examples/09.USB/Keyboard/KeyboardReprogram/KeyboardReprogram.ino

@@ -13,7 +13,7 @@
  a final key combination (CTRL-U).
  
  Circuit:
- * Arduino Leonardo
+ * Arduino Leonardo or Arduino Due
  * wire to connect D2 to ground.
  
  created 5 Mar 2012