Update sms_st_nonrecurring-server-wmi-class.md

Author: mestew

memdocs/configmgr/develop/reference/core/servers/configure/sms_st_nonrecurring-server-wmi-class.md

@@ -1,6 +1,7 @@
 ---
 title: "SMS_ST_NonRecurring Class"
 titleSuffix: "Configuration Manager"
+description: "A Windows Management Instrumentation class that that represents a schedule token for non-recurring events."
 ms.date: "09/20/2016"
 ms.prod: "configuration-manager"
 ms.technology: configmgr-sdk