one more wording tweak

Author: nedbat

Doc/tools/templates/indexcontent.html

@@ -56,7 +56,7 @@ <h1>{{ docstitle|e }}</h1>
          <span class="linkdescr"> {% trans whatsnew_index=pathto("whatsnew/index") %}Or <a href="{{ whatsnew_index }}">all "What's new" documents since Python 2.0</a>{% endtrans %}</span></li>
       <li class="biglink"><a class="biglink" href="{{ pathto("tutorial/index") }}">{% trans %}Tutorial{% endtrans %}</a><br>
          <span class="linkdescr">{% trans %}Start here: a tour of Python's syntax and features{% endtrans %}</span></li>
-      <li class="biglink"><a class="biglink" href="{{ pathto("library/builtin-index") }}">{% trans %}Built-in reference{% endtrans %}</a><br>
+      <li class="biglink"><a class="biglink" href="{{ pathto("library/builtin-index") }}">{% trans %}Built-ins reference{% endtrans %}</a><br>
          <span class="linkdescr">{% trans %}Built-in functions and classes{% endtrans %}</span></li>
       <li class="biglink"><a class="biglink" href="{{ pathto("library/index") }}">{% trans %}Library reference{% endtrans %}</a><br>
          <span class="linkdescr">{% trans %}Standard library modules{% endtrans %}</span></li>