Documentation: Add note about suppression of sub-folder mode

public/documentation/changelog.html

@@ -89,6 +89,7 @@
         <li>Wiki: The wiki tool is not available *yet*. It will be included again in future versions, but there were too many changes required to include it in v2.0.</li>
         <li>Blogs: The blogs tool is not available. It might be included again in future versions, but there were too many changes required to include it in v2.0.</li>
         <li>Dropbox: The dropbox tool is not available. It might be included again in future versions, but there were too many changes required to include it in v2.0.</li>
+        <li>Global: Sub-folder mode: Chamilo 2 will not support being installed in a sub-folder. Nowadays, defining a subdomain has become very easy and provides higher security and more configuration flexibility, and supporting sub-folders is a complex task.</li>
     </ul>
 
     <h3>Known issues</h3>