Avoid leaking tickers

In Go 1.22 and earlier, a ticker needs to be explicitly stopped
when it's no longer useful in order to avoid a resource leak.
In Go 1.23 and later, an orphaned ticker will eventually be
garbage collected, but it's still more thrifty to stop it early.

examples/data-channels-detach/main.go

@@ -150,7 +150,9 @@ func ReadLoop(d io.Reader) {
 
 // WriteLoop shows how to write to the datachannel directly
 func WriteLoop(d io.Writer) {
-	for range time.NewTicker(5 * time.Second).C {
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+	for range ticker.C {
 		message, err := randutil.GenerateCryptoRandomString(messageSize, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
 		if err != nil {
 			panic(err)