ListOptions: fix the doc on ResourceVersion

pkg/api/types.go

@@ -2226,7 +2226,11 @@ type ListOptions struct {
 	FieldSelector fields.Selector
 	// If true, watch for changes to this list
 	Watch bool
-	// The resource version to watch (no effect on list yet)
+	// For watch, it's the resource version to watch.
+	// For list,
+	// - if unset, then the result is returned from remote storage based on quorum-read flag;
+	// - if it's 0, then we simply return what we currently have in cache, no guarantee;
+	// - if set to non zero, then the result is as fresh as given rv.
 	ResourceVersion string
 	// Timeout for the list/watch call.
 	TimeoutSeconds *int64