Issue #28900: Update documentation sidebar for 3.6.0rc.

diff --cc Doc/tools/templates/indexsidebar.html
index bb449ef1cd30a602584f082de9f6b6f42a22ad9d,e222a461f27f358b48ff2c24e95ec5e5bbc20b28..413c0a7699cbe83563121f3592d079c3e5a35d25
--- 1/Doc/tools/templates/indexsidebar.html
--- 2/Doc/tools/templates/indexsidebar.html
+++ b/Doc/tools/templates/indexsidebar.html
@@@ -3,7 -3,8 +3,8 @@@
  <h3>{% trans %}Docs for other versions{% endtrans %}</h3>
  <ul>
    <li><a href="https://docs.python.org/2.7/">{% trans %}Python 2.7 (stable){% endtrans %}</a></li>
-   <li><a href="https://docs.python.org/3.4/">{% trans %}Python 3.4 (stable){% endtrans %}</a></li>
 -  <li><a href="https://docs.python.org/3.6/">{% trans %}Python 3.6 (pre-release){% endtrans %}</a></li>
++  <li><a href="https://docs.python.org/3.5/">{% trans %}Python 3.5 (stable){% endtrans %}</a></li>
+   <li><a href="https://docs.python.org/3.7/">{% trans %}Python 3.7 (in development){% endtrans %}</a></li>
    <li><a href="https://www.python.org/doc/versions/">{% trans %}Old versions{% endtrans %}</a></li>
  </ul>