Fix command to match example

Author: FrickinCode

src/azure-cli/azure/cli/command_modules/cdn/aaz/latest/afd/endpoint/_purge.py

@@ -18,7 +18,7 @@ class Purge(AAZCommand):
     """Removes a content from AzureFrontDoor.
 
     :example: Remove all cached contents under directory "/script" for domain www.contoso.com
-        az afd endpoint purge -g group --profile-name profile --domains [www.contoso.com,www.contoso1.com] --content-paths '/scripts/*'
+        az afd endpoint purge -g group --profile-name profile --domains www.contoso.com --content-paths '/scripts/*'
     """
 
     _aaz_info = {