all: use any instead of interface{}

My favorite part of generics.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>

net/dns/resolver/tsdns.go

@@ -711,7 +711,7 @@ type response struct {
 }
 
 var dnsParserPool = &sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return new(dnsParser)
 	},
 }

net/dns/resolver/tsdns_server_test.go

@@ -221,7 +221,7 @@ func weirdoGoCNAMEHandler(target string) dns.HandlerFunc {
 // provided.
 //
 // Types supported: netaddr.IP.
-func dnsHandler(answers ...interface{}) dns.HandlerFunc {
+func dnsHandler(answers ...any) dns.HandlerFunc {
 	return func(w dns.ResponseWriter, req *dns.Msg) {
 		m := new(dns.Msg)
 		m.SetReply(req)
@@ -303,7 +303,7 @@ func dnsHandler(answers ...interface{}) dns.HandlerFunc {
 	}
 }
 
-func serveDNS(tb testing.TB, addr string, records ...interface{}) *dns.Server {
+func serveDNS(tb testing.TB, addr string, records ...any) *dns.Server {
 	if len(records)%2 != 0 {
 		panic("must have an even number of record values")
 	}

net/dns/resolver/tsdns_test.go

@@ -454,7 +454,7 @@ func TestDelegate(t *testing.T) {
 	// intend to handle responses this large, so there should be truncation.
 	hugeTXT := generateTXT(64000, randSource)
 
-	records := []interface{}{
+	records := []any{
 		"test.site.",
 		resolveToIP(testipv4, testipv6, "dns.test.site."),
 		"LCtesT.SiTe.",
@@ -1105,7 +1105,7 @@ func TestHandleExitNodeDNSQueryWithNetPkg(t *testing.T) {
 		t.Skip("skipping test on Windows; waiting for golang.org/issue/33097")
 	}
 
-	records := []interface{}{
+	records := []any{
 		"no-records.test.",
 		dnsHandler(),