Undo faulty change of doc comment

Author: bewee

Diff for: src/adapter/adapter_trait.rs

@@ -26,7 +26,12 @@ use webthings_gateway_ipc_types::DeviceWithoutId;
 /// struct ExampleAdapter;
 ///
 /// #[async_trait]
-/// impl Adapter for ExampleAdapter {}
+/// impl Adapter for ExampleAdapter {
+///     async fn on_remove_device(&mut self, device_id: String) -> Result<(), String> {
+///         log::debug!("Device {} removed", device_id);
+///         Ok(())
+///     }
+/// }
 ///
 /// impl ExampleAdapter {
 /// #   pub fn new(adapter_handle: AdapterHandle) -> Self {