Rename TimeSyncStatus() to TimeSynced() for API clarity

example/updater/main.go

@@ -113,7 +113,7 @@ func updateThenReboot() {
 	defer updater.Close()
 
 	log.Println("checking time sync")
-	synced, err := updater.TimeSyncStatus()
+	synced, err := updater.TimeSynced()
 	if err != nil {
 		log.Fatal(err)
 	}