Main.WebHome of default wiki is not valid XHTML

/database/target/xar/Main/WebHome contains a line like this:
1. Changing the layout and menu contents by using the [Panel Wizard>Panels.PanelWizard?forceLeftPanels=1&forceRightPanels=1]

This is rendered to:
<li>Changing the layout and menu contents by using the <span class="wikilink"><a href="/xwiki/bin/view/Panels/PanelWizard?forceLeftPanels=1&forceRightPanels=1">Panel Wizard</a></span></li>

Which is invalid XHTML, since the attribute value contains a "&" symbol.

As a general idea for catching this sort of bugs I propose to build a functional test that checks the validity of all documents in the default wiki (after rendering); see XWIKI-1275.