[css-text-3] Update Changes section

Author: frivoal

css-text-3/Overview.bs

@@ -5127,6 +5127,8 @@ Changes</h2>
   * Use ''allow-end'' hanging rules rather than ''force-end'' rules for trailing white space;
     define how it impacts intrinsic size contributions of text.
     (<a href="https://github.com/w3c/csswg-drafts/issues/3440">Issue 3440</a>)
+  * Generalize the logic that handles spaces at the end of lines to
+    sequences of Unicode Zs spaces (except NBSP), not just of Space U+0020.
 
   <h3 class="no-num" id="changes-2018-12-06">
   Changes from the <a href="https://www.w3.org/TR/2018/WD-css-text-3-20181206/">6 December 2018 Working Draft</a></h3>