ROSA change name of Cluster Admin -> Nodes book

Author: Michael Burke

_topic_maps/_topic_map_rosa.yml

@@ -421,7 +421,7 @@ Topics:
     File: dedicated-aws-dc
 - Name: Cluster autoscaling
   File: rosa-cluster-autoscaling
-- Name: Nodes
+- Name: Manage nodes using machine pools 
   Dir: rosa_nodes
   Distros: openshift-rosa
   Topics: