ipv6: update RFC number of IPv6 specification in docs

Change-Id: I38980c8463b7806c129024967713125acf663b82
Reviewed-on: https://go-review.googlesource.com/49791
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

ipv6/doc.go

@@ -8,7 +8,7 @@
 // The package provides IP-level socket options that allow
 // manipulation of IPv6 facilities.
 //
-// The IPv6 protocol is defined in RFC 2460.
+// The IPv6 protocol is defined in RFC 8200.
 // Socket interface extensions are defined in RFC 3493, RFC 3542 and
 // RFC 3678.
 // MLDv1 and MLDv2 are defined in RFC 2710 and RFC 3810.

ipv6/icmp.go

@@ -29,7 +29,7 @@ func (typ ICMPType) Protocol() int {
 // packets. The filter belongs to a packet delivery path on a host and
 // it cannot interact with forwarding packets or tunnel-outer packets.
 //
-// Note: RFC 2460 defines a reasonable role model. A node means a
+// Note: RFC 8200 defines a reasonable role model. A node means a
 // device that implements IP. A router means a node that forwards IP
 // packets not explicitly addressed to itself, and a host means a node
 // that is not a router.