Fix reference

Author: mnot

draft-ietf-quic-spin-exp.md

@@ -221,7 +221,7 @@ information is considered low.
 
 # Acknowledgments
 
-This document is derived from {{QUIC-SPIN}}, which was the work of the
+This document is derived from {{I-D.trammell-quic-spin}}, which was the work of the
 following authors in addition to the editor of this document:
 
 - Piet De Vaere, ETH Zurich