Update to go1.25.4

src/net/url/url.go

@@ -673,13 +673,13 @@ func parseHost(host string) (string, error) {
 
 		// Per RFC 3986, only a host identified by a valid
 		// IPv6 address can be enclosed by square brackets.
-		// This excludes any IPv4 or IPv4-mapped addresses.
+		// This excludes any IPv4, but notably not IPv4-mapped addresses.
 		addr, err := netip.ParseAddr(unescapedHostname)
 		if err != nil {
 			return "", fmt.Errorf("invalid host: %w", err)
 		}
-		if addr.Is4() || addr.Is4In6() {
-			return "", errors.New("invalid IPv6 host")
+		if addr.Is4() {
+			return "", errors.New("invalid IP-literal")
 		}
 		return "[" + unescapedHostname + "]" + unescapedColonPort, nil
 	} else if i := strings.LastIndex(host, ":"); i != -1 {