added link to theses page to teaching dropdown menu

Author: tobideusser

_includes/navigation.html

@@ -24,6 +24,7 @@
           <a href="{{ site.baseurl }}/teaching/">Courses Overview</a>
           <a href="{{ site.baseurl }}/teaching/ilsds25/">ILSDS (WS 25)</a>
           <a href="{{ site.baseurl }}/teaching/mmdi25/">MMD1 (WS 25)</a>
+          <a href="{{ site.baseurl }}/teaching/theses">Theses</a>
         </div>
       </li>