[css-text-3] Update DoC

Author: fantasai

css-text-3/Overview.bs

@@ -6638,6 +6638,9 @@ Acknowledgements</h2>
 <h2 class="no-num" id="changes" oldids="recent-changes">
 Changes</h2>
 
+  See <a href="https://drafts.csswg.org/css-text-3/issues-lc-2013">Disposition of Comments</a>
+  covering all comments since 2013.
+
   <h3 class="no-num" id="changes-2020-04-29">
   Changes from the <a href="https://www.w3.org/TR/2020/WD-css-text-3-20200429/">29 April 2020 Working Draft</a></h3>