[Aks] Update doc (#16678)

* Update doc

* Save

Co-authored-by: wyunchi-ms <yunwang@microsoft.com>

Author: wyunchi-ms

src/Aks/Aks/help/New-AzAksCluster.md

@@ -10,6 +10,10 @@ schema: 2.0.0
 ## SYNOPSIS
 Create a new managed Kubernetes cluster.
 
+The cmdlet may call below Microsoft Graph API according to input parameters:
+
+- POST /servicePrincipals
+
 ## SYNTAX
 
 ```