all: use Go 1.22 range-over-int

Updates #11058

Change-Id: I35e7ef9b90e83cac04ca93fd964ad00ed5b48430
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

ipn/localapi/debugderp.go

@@ -247,7 +247,7 @@ func (h *Handler) serveDebugDERPRegion(w http.ResponseWriter, r *http.Request) {
 		// Next, repeatedly get the server key to see if the node is
 		// behind a load balancer (incorrectly).
 		serverPubKeys := make(map[key.NodePublic]bool)
-		for i := 0; i < 5; i++ {
+		for i := range 5 {
 			func() {
 				rc := derphttp.NewRegionClient(fakePrivKey, h.logf, h.netMon, func() *tailcfg.DERPRegion {
 					return &tailcfg.DERPRegion{

ipn/localapi/localapi.go

@@ -903,7 +903,7 @@ func (h *Handler) serveDebugDialTypes(w http.ResponseWriter, r *http.Request) {
 	}
 
 	wg.Wait()
-	for i := 0; i < len(dialers); i++ {
+	for range len(dialers) {
 		res := <-results
 		fmt.Fprintf(w, "[%s] connected=%v err=%v\n", res.name, res.conn != nil, res.err)
 		if res.conn != nil {