[css-transitions-2] Add TR URL.

Author: dbaron

css-transitions-2/Overview.bs

@@ -23,6 +23,7 @@ Work Status: Exploring
 Shortname: css-transitions
 Level: 2
 Group: csswg
+TR: https://www.w3.org/TR/css-transitions-2/
 ED: https://drafts.csswg.org/css-transitions-2/
 Editor: L. David Baron, Google https://www.google.com, https://dbaron.org/, w3cid 15393
 Editor: Brian Birtles, Invited Expert, brian@birchill.co.jp, w3cid 43194