Updated Perform basic lighting (markdown)

Perform-basic-lighting.md

@@ -11,6 +11,8 @@ This code would set the color of the A-key on your keyboard to red and the color
 All other keys would keep the color they had before:
 ```C#
 CorsairKeyboard keyboard = CueSDK.KeyboardSDK;
+keyboard.Brush = (SolidColorBrush)Color.Transparent; // This 'enables' manual color changes.
+
 keyboard['A'].Color = Color.Red;
 keyboard[CorsairKeyboardKeyId.B].Color = Color.Green;
 keyboard.Update();