Make tags sideblock heading link to my tags page

Signed-off-by: Richard Mansfield <richardm@catalyst.net.nz>

htdocs/theme/raw/templates/sideblocks/tags.tpl

-<h3>{str tag="tags"}</h3>
+<h3><a href="{$WWWROOT}tags.php">{str tag="tags"}</a></h3>
 <div class="sidebar-content tags">
 {if $data.tags}
   {foreach from=$data.tags item=tag}