docs: clusterResources in declarative cluster config (#10219)

* docs: clusterResources in declarative cluster config

Signed-off-by: CI <michael@crenshaw.dev>

* add article

Signed-off-by: CI <michael@crenshaw.dev>

Signed-off-by: CI <michael@crenshaw.dev>

docs/operator-manual/declarative-setup.md

@@ -489,6 +489,7 @@ The secret data must include following fields:
 * `name` - cluster name
 * `server` - cluster api server url
 * `namespaces` - optional comma-separated list of namespaces which are accessible in that cluster. Cluster level resources would be ignored if namespace list is not empty.
+* `clusterResources` - optional boolean string (`"true"` or `"false"`) determining whether Argo CD can manage cluster-level resources on this cluster. This setting is used only if the list of managed namespaces is not empty.
 * `config` - JSON representation of following data structure:
 
 ```yaml