[css-typed-om] Add TR link to typed OM

Addresses w3c#314 for typed OM

Author: shans

css-typed-om/Overview.bs

@@ -3,6 +3,7 @@ Title:  CSS Typed OM Level 1
 Status: ED
 Group: houdini
 ED: https://drafts.css-houdini.org/css-typed-om-1/
+TR: https://www.w3.org/TR/2016/WD-css-typed-om-1-20160607/
 Previous Version: https://www.w3.org/TR/2016/WD-css-typed-om-1-20160607/
 Shortname: css-typed-om
 Level: 1