doc: fix broken links in left-hand TOC

Due to recent renamings.

Author: bluetech

doc/en/_templates/globaltoc.html

@@ -4,9 +4,9 @@ <h3><a href="{{ pathto(master_doc) }}">{{ _('Table Of Contents') }}</a></h3>
   <li><a href="{{ pathto('index') }}">Home</a></li>
   <li><a href="{{ pathto('getting-started') }}">Get started</a></li>
   <li><a href="{{ pathto('example/index') }}">Examples</a></li>
-  <li><a href="{{ pathto('customize') }}">Customize</a></li>
-  <li><a href="{{ pathto('reference') }}">API Reference</a></li>
-  <li><a href="{{ pathto('plugin_list') }}">3rd party plugins</a></li>
+  <li><a href="{{ pathto('reference/customize') }}">Customize</a></li>
+  <li><a href="{{ pathto('reference/reference') }}">API Reference</a></li>
+  <li><a href="{{ pathto('reference/plugin_list') }}">3rd party plugins</a></li>
   <li><a href="{{ pathto('contents') }}">Complete table of contents</a></li>
   <li><a href="{{ pathto('changelog') }}">Changelog</a></li>
   <li><a href="{{ pathto('contributing') }}">Contributing</a></li>