Update storage-files-identity-auth-active-directory-enable.md

Author: yuemlu

articles/storage/files/storage-files-identity-auth-active-directory-enable.md

@@ -59,7 +59,7 @@ Before you enable AD authentication for Azure file shares, make sure you have co
 
 Azure Files AD authentication (preview) is available in [most public regions](https://azure.microsoft.com/global-infrastructure/regions/) except for:
 
-NOT Supported
+Azure Files AD authentication is not available in:
 - West US
 - West US 2
 - East US