message: Add documentation for "remove failed node"
diff: @@ -45,6 +45,7 @@ After a [discussion](https://github.com/OpenZWave/Zwave2Mqtt/issues/201) with Op
  - [Add a node](#add-a-node)
  - [Remove a node](#remove-a-node)
  - [Replace failed node](#replace-failed-node)
  + - [Remove a failed node](#remove-a-failed-node)
  - [:star: Features](#star-features)
  - [:robot: Home Assistant integration (BETA)](#robot-home-assistant-integration-beta)
  - [Components management](#components-management)
  @@ -333,6 +334,15 @@ To add a node using the UI select the controller Action `Remove Node (exclusion)
  To replace a failed node from the UI you have to use the command `Replace Failed Node`, if everything is ok the controller will start inclusion mode and status will be `Waiting`, now enable inclusion on your device to add it to the network by replacing the failed one.
  +### Remove a failed node
  +
  +If a node is missing or marked as dead. There is a way to cleanup the controller by executing `Remove Failed Node`. This will forcebly delete the node from the controller.
  +It can only succeed if:
  + - Node has ben first marked as failed using `Has node failed`
  + - Marked as Dead by the controller
  +
  +Alive and Sleeping nodes cannot be deleted.
  +
  ## :star: Features
  - Configurable Zwave to Mqtt Gateway
  