Remove non-existing power channel (#15570)

Migrating from OH 2.5 I tripped over this, as :power no longer exists and instead one has to send ON/OFF commands to the :color channel instead.

Looks like documentation wasn't fully updated with the code changes.

Signed-off-by: uqs <uqs@FreeBSD.org>

bundles/org.openhab.binding.nanoleaf/README.md

@@ -225,7 +225,7 @@ e.g. via command line `curl --location --request POST 'http://<address>:16021/ap
 
 Note: If you auto-discovered your things and items:
 
-- A controller item looks like nanoleaf:controller:F0ED4F9351AF:power where F0ED4F9351AF is the id of the controller that has been automatically assigned by the binding.
+- A controller item looks like nanoleaf:controller:F0ED4F9351AF:color where F0ED4F9351AF is the id of the controller that has been automatically assigned by the binding.
 - A panel item looks like nanoleaf:lightpanel:F0ED4F9351AF:39755:singleTap where 39755 is the id of the panel that has been automatically assigned by the binding.
 
 ```java