Normative: Require the latest available Unicode version instead of a fixed version number

Ref. tc39/ecma262#620.

Author: mathiasbynens

spec/normative-references.html

@@ -43,10 +43,10 @@ <h1>Normative References</h1>
       <a href="http://www.iana.org/time-zones/">IANA Time Zone Database</a>
     </li>
     <li>
-      <a href="http://www.unicode.org/versions/latest">The Unicode Standard, Version 8.0.0, or successor</a>
+      <a href="http://www.unicode.org/versions/latest">The Unicode Standard</a>
     </li>
     <li>
-      <a href="http://unicode.org/reports/tr35/">Unicode Technical Standard 35, Unicode Locale Data Markup Language, version 28 or successor</a>
+      <a href="http://www.unicode.org/reports/tr35/">Unicode Technical Standard 35, Unicode Locale Data Markup Language</a>
     </li>
   </ul>