Add TR link

Author: svgeesus

css-shadow-parts-1/Overview.bs

@@ -6,6 +6,7 @@ Group: CSSWG
 Status: ED
 Work Status: exploring
 URL: http://drafts.csswg.org/css-shadow-parts/
+TR: https://www.w3.org/TR/css-shadow-parts-1/
 Editor: Tab Atkins-Bittner, Google, http://xanthir.com/contact/, w3cid 42199
 Editor: Fergal Daly, Google, fergal@chromium.org
 Abstract: This specification defines the ''::part()'' pseudo-element on <a>shadow hosts</a>, allowing <a>shadow hosts</a> to selectively expose chosen elements from their <a>shadow tree</a> to the outside page for styling purposes.