fix lines in list endpoint

main.go

@@ -147,7 +147,7 @@ func main() {
 		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 		for i, link := range links {
 			if i > 0 {
-				_, _ = w.Write([]byte("\n"))
+				_, _ = w.Write([]byte("\n\n"))
 			}
 			_, _ = w.Write([]byte(link))
 		}
@@ -185,6 +185,7 @@ func pollSource(ctx context.Context, source string, interval time.Duration, cach
 	for {
 		select {
 		case <-ctx.Done():
+			log.Printf("poller shutdown")
 			return
 		case <-ticker.C:
 			runOnce(ctx, source, cacheDir, agg, client)