gitweb: shortlog template: removed excessive whitespace, added title bar.
The title bar is currently empty, this is just a preparation for filling it
with content.
<item>
<title>#tag|escape#</title>
<link>{urlbase}{url}rev/{node|short}</link>
<description><![CDATA[#tag|strip|escape|addbreaks#]]></description>
<pubDate>#date|rfc822date#</pubDate>
</item>