{AzureFrontDoor} fixes Azure#5170

fixes Azure/issues/5170

For managing Azure Front Door Standard/Premium, please refer https://docs.microsoft.com/en-us/cli/azure/afd?view=azure-cli-latest.
For classical Azure Front Door, please refer https://docs.microsoft.com/en-us/cli/azure/network/front-door?view=azure-cli-latest.

src/front-door/azext_front_door/_help.py

@@ -10,7 +10,7 @@
 # region FrontDoor
 helps['network front-door'] = """
     type: group
-    short-summary: Manage Front Doors.
+    short-summary: Manage Classical Azure Front Doors. For managing Azure Front Door Standard/Premium, please refer https://docs.microsoft.com/en-us/cli/azure/afd?view=azure-cli-latest.
 """
 
 helps['network front-door create'] = """