README, protocol: fix links to RFC 5730

Author: ydnar

README.md

@@ -5,7 +5,7 @@
 
 Extensible Provisioning Protocol (EPP) for [Go](https://go.dev/).
 
-[EPP](https://tools.ietf.org/html/rfc5730) is an XML-based protocol for provisioning and managing domain names and other objects at domain name registries. The underlying transport is usually TLS, secured with password authentication, IP allow lists, and [mTLS](https://en.wikipedia.org/wiki/Mutual_authentication).
+[EPP](https://datatracker.ietf.org/doc/rfc5730/) is an XML-based protocol for provisioning and managing domain names and other objects at domain name registries. The underlying transport is usually TLS, secured with password authentication, IP allow lists, and [mTLS](https://en.wikipedia.org/wiki/Mutual_authentication).
 
 **Note:** This is a fork of [domainr/epp](https://github.com/domainr/epp) to develop and test the next version of its API. You should probably use it instead.
 

protocol/client.go

@@ -14,8 +14,10 @@ import (
 )
 
 // Client is a low-level client for the Extensible Provisioning Protocol (EPP)
-// as defined in RFC 3790. See https://www.rfc-editor.org/rfc/rfc5730.html.
+// as defined in [RFC 5730].
 // A Client is safe to use from multiple goroutines.
+//
+// [RFC 5730]: https://datatracker.ietf.org/doc/rfc5730/
 type Client interface {
 	// Command sends an EPP command and returns an EPP response.
 	// It blocks until a response is received, ctx is canceled, or