Updated table descriptions

Author: pabel-rh

modules/using-kubernetes-custom-actions/ref-supported-kubernetes-custom-actions.adoc

@@ -24,21 +24,21 @@ Creates a namespace for the Kubernetes cluster in the {product-short}.
 
 |`clusterRef`
 |`string`
-|Optional if `url` is defined
+|Required if `url` is not defined. You must specify either `url` or `clusterRef`.
 |Cluster resource entity reference from the catalog
 |`bar`
 
 |`url`
 |`string`
-|Optional if `clusterRef` is defined
+|Required if `clusterRef` is not defined. You must specify either `url` or `clusterRef`.
 |API url of the Kubernetes cluster
-| `https://api.foo.redhat.com:6443`
+|`https://api.foo.redhat.com:6443`
 
 |`token`
 |`String`
 |Required
 |Kubernetes API bearer token used for authentication
-| 
+|
 
 |`skipTLSVerify`
 |`boolean`