References: point at the live IANA registry

RFC 6890 defines the IPv4 Special-Purpose Address Registry and
its fields, but the tables it contains are a snapshot taken at
publication. Cite the live registry alongside it, and say which
of the two carries current contents.

From adoption-call review (T. Petch).

New informative reference: IANA-IPV4-SPECIAL.

Closes #9

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: remcovm

draft-ietf-intarea-ipv6-resolved-gateway.md

@@ -37,6 +37,11 @@ normative:
   RFC8950:
 
 informative:
+  IANA-IPV4-SPECIAL:
+    target: https://www.iana.org/assignments/iana-ipv4-special-registry/
+    title: "IPv4 Special-Purpose Address Registry"
+    author:
+      - org: "IANA"
   RFC1027:
   RFC1122:
   I-D.ietf-intarea-v4-via-v6:
@@ -527,6 +532,9 @@ IETF Last Call.
 This document requests that IANA assign a single IPv4 address from
 the 192.0.0.0/24 IETF Protocol Assignments block in the
 "IANA IPv4 Special-Purpose Address Registry" {{RFC6890}}. The
+current contents of that registry are maintained by IANA at
+{{IANA-IPV4-SPECIAL}}; {{RFC6890}} defines the registry and its
+fields, but its tables are a snapshot taken at publication. The
 address `192.0.0.11/32` is suggested. The assigned value is
 referred to as `IPV4-SENTINEL` (TBD1) throughout this document.