Fix URL reference

Author: johngray-dev

working/doc/spec/references.md

@@ -72,7 +72,7 @@ URL: <http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5389557>
 
 M. Ounsworth, J. Gray, M. Pala, J. Klaußner, S. Fluher. "Composite ML-DSA for use in X.509 Public Key Infrastructure", January 2026
 
-URL: https://datatracker.ietf.org/doc/draft-ietf-lamps-pq-composite-sigs/14/
+URL: <https://datatracker.ietf.org/doc/draft-ietf-lamps-pq-composite-sigs/14/>
 
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