Introduce ClusterCloudEventSource (#1398)

content/docs/2.15/operate/cloud-events.md

@@ -50,7 +50,21 @@ In general, an event emitted by KEDA would fundamentally come down to the follow
    }
 }
 ```
+### Scopes: Namespace vs. Cluster
 
+Each `CloudEventSource` is defined in one namespace and will only subscribe to events inside that namespace. If you want to subscribe to events in all namespaces, you can instead create a `ClusterCloudEventSource` resource.
+
+Defining a `ClusterCloudEventSource` works almost identically to a `CloudEventSource`, except there is no `metadata.namespace` value:
+
+```yaml
+apiVersion: keda.sh/v1alpha1
+kind: ClusterCloudEventSource
+metadata:
+  name: {cluster-cloudeventsource-name}
+spec:
+  # As before ..
+```
+
 ## Event Sinks
 
 There will be multiple types of destination to emit KEDA events to.