Change references to 3168 to be normative

I'm not sure if all of them need to be normative or not?

draft-ietf-quic-recovery.md

@@ -795,7 +795,7 @@ is sent on a PTO timer expiration (see {{pto}}) or when entering recovery
 
 ## Explicit Congestion Notification {#congestion-ecn}
 
-If a path has been validated to support ECN ({{?RFC3168}}, {{?RFC8311}}), QUIC
+If a path has been validated to support ECN ({{!RFC3168}}, {{?RFC8311}}), QUIC
 treats a Congestion Experienced (CE) codepoint in the IP header as a signal of
 congestion. This document specifies an endpoint's response when the
 peer-reported ECN-CE count increases; see Section 13.4.2 of {{QUIC-TRANSPORT}}.
@@ -1123,15 +1123,15 @@ A sender can detect suppression of reports by marking occasional packets that it
 sends with an ECN-CE marking. If a packet sent with an ECN-CE marking is not
 reported as having been CE marked when the packet is acknowledged, then the
 sender can disable ECN for that path by not setting ECT codepoints in subsequent
-packets sent on that path {{?RFC3168}}.
+packets sent on that path {{!RFC3168}}.
 
 Reporting additional ECN-CE markings will cause a sender to reduce their sending
 rate, which is similar in effect to advertising reduced connection flow control
 limits and so no advantage is gained by doing so.
 
 Endpoints choose the congestion controller that they use. Congestion controllers
 respond to reports of ECN-CE by reducing their rate, but the response may vary.
-Markings can be treated as equivalent to loss ({{?RFC3168}}), but other
+Markings can be treated as equivalent to loss ({{!RFC3168}}), but other
 responses can be specified, such as ({{?RFC8511}}) or ({{?RFC8311}}).