add support for an "LED Toggle" key

ArduinoKeyboard.ino

@@ -405,6 +405,14 @@ void handle_synthetic_key_press(byte switchState, Key mappedKey) {
       Keyboard.consumerControl(mappedKey.rawKey);
     }
   }
+  
+  else if (mappedKey.flags & IS_INTERNAL) {
+        if (key_toggled_on (switchState)) {
+          if (mappedKey.rawKey == LED_TOGGLE) {
+             next_led_mode(); 
+          }
+        }
+  }
   else if (mappedKey.flags & IS_SYSCTL) {
     if (key_toggled_on (switchState)) {
       Keyboard.systemControl(mappedKey.rawKey);

key_defs.h

@@ -19,6 +19,12 @@ typedef struct {
 #define IS_MACRO       B00000001
 #define IS_SYSCTL      B00000010
 #define IS_CONSUMER    B00000100
+#define IS_INTERNAL    B00001000
+
+
+// IS_INTERNAL key table:
+
+#define LED_TOGGLE 1
 
 
 #define MOUSE_UP            B0000001
@@ -427,3 +433,7 @@ typedef struct {
 
 
 
+
+#define Key_LEDEffectNext (Key) { KEY_FLAGS | SYNTHETIC_KEY | IS_INTERNAL, LED_TOGGLE }
+
+