Update feature_rgblight.md to note that for split dual-mcu boards,
both sides must be flash to get the new value of the rgblight_layers.
https://github.com/qmk/qmk_firmware/pull/7768#issuecomment-
600237611
}
```
+Note: For split keyboards with two controllers, both sides need to be flashed when updating the contents of rgblight_layers.
+
## Functions
If you need to change your RGB lighting in code, for example in a macro to change the color whenever you switch layers, QMK provides a set of functions to assist you. See [`rgblight.h`](https://github.com/qmk/qmk_firmware/blob/master/quantum/rgblight.h) for the full list, but the most commonly used functions include: