Add documentation around webhooks_notifications for databricks_job (#1968)

* Add documentation around webhooks_notifications

* Create job.md

* Update job.md

* Update job.md

Author: fuselessmatt

docs/resources/job.md

@@ -128,6 +128,17 @@ Each entry in `webhook_notification` block takes a list `webhook` blocks. The fi
 * `on_success` - (Optional) (List) list of notification IDs to call when the run completes successfully. A maximum of 3 destinations can be specified.
 * `on_failure` - (Optional) (List) list of notification IDs to call when the run fails. A maximum of 3 destinations can be specified.
 
+Note that the `id` is not to be confused with the name of the alert destination. The `id` can be retrieved through the API or the URL of Databricks UI `https://<workspace host>/sql/destinations/<notification id>?o=<workspace id>`
+
+Example
+```hcl
+ webhook_notifications {
+    on_failure {
+      id = "fb99f3dc-a0a0-11ed-a8fc-0242ac120002"
+    }
+  }
+```
+
 ### webhook Configuration Block
 
 * `id` - ID of the system notification that is notified when an event defined in `webhook_notifications` is triggered.