Cite draft-ietf-tls-svcb-ech for ECH in DNS

draft-ietf-tls-esni.md

@@ -167,8 +167,11 @@ A client-facing server enables ECH by publishing an ECH configuration, which
 is an encryption public key and associated metadata. The server must publish
 this for all the domains it serves via Shared or Split Mode. This document
 defines the ECH configuration's format, but delegates DNS publication details
-to {{!HTTPS-RR=I-D.ietf-dnsop-svcb-https}}. Other delivery mechanisms are also
-possible. For example, the client may have the ECH configuration preconfigured.
+to {{!HTTPS-RR=I-D.ietf-dnsop-svcb-https}}. See
+{{!ECH-IN-DNS=I-D.ietf-tls-svcb-ech}} for specifics about how ECH
+configurations are advertised in HTTPS records. Other delivery mechanisms are
+also possible. For example, the client may have the ECH configuration
+preconfigured.
 
 When a client wants to establish a TLS session with some backend server, it
 constructs a private ClientHello, referred to as the ClientHelloInner.