udpate documentation

doc/frontend.md

@@ -1076,7 +1076,7 @@ This prototype contain all valid section with all valid `key=value` pair.
     @extdepends = ()
     @contents = ()
     @options = ( log env pipeline )
-    @flags = ( down nosetsid )
+    @flags = ( down )
     @notify =
     @user = ()
     @timeout-finish =