Update keyboardModifiers.adoc

Fixed the issue arduino#610 
Updated the documentation for F13-F24
Fixed misleading definition in line 25

Author: animeshsrivastava24

Language/Functions/USB/Keyboard/keyboardModifiers.adoc

@@ -22,7 +22,7 @@ For more on ASCII values and the characters or functions they represent, see htt
 [%hardbreaks]
 For multiple key presses use link:../keyboardpress[Keyboard.press]()
 [%hardbreaks]
-The Leonardo's definitions for modifier keys are listed below:
+The definitions of the modifier keys are listed below:
 [%hardbreaks]
 
 
@@ -64,6 +64,18 @@ The Leonardo's definitions for modifier keys are listed below:
 |KEY_F10	|0xCB	|203
 |KEY_F11	|0xCC	|204
 |KEY_F12	|0xCD	|205
+|KEY_F13  |0xF0 |240
+|KEY_F14  |0xF1 |241
+|KEY_F15  |0xF2 |242
+|KEY_F16  |0xF3 |243
+|KEY_F17  |0xF4 |244
+|KEY_F18  |0xF5 |245
+|KEY_F19  |0xF6 |246
+|KEY_F20  |0xF7 |247
+|KEY_F21  |0xF8 |248
+|KEY_F22  |0xF9 |249
+|KEY_F23  |0xFA |250
+|KEY_F24  |0xFB |251
 |===
 
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