feat: add metrics to changelog

Author: mjang

content/nginx-one/changelog.md

@@ -34,10 +34,15 @@ Stay up-to-date with what's new and improved in the F5 NGINX One Console.
 
 ### Added observability features
 
-You can now visualize the following items from the NGINX One Console:
+For each instance, you can now visualize the following items from the NGINX One Console:
 
-- a
-- b
+- Network traffic
+- Connections (active and idle)
+- Requests
+- Response codes
+- Memory and CPU utilization
+
+To access this screen, select **Manage** > **Instances**, select an instance, selct an instance hostname, and then select the **Metrics** tab.
 
 ## July 15, 2025