img: add support for objects too

[ikiwiki] / t / secret.rss

<?xml version="1.0"?>
<rss version="2.0">
<channel>
<title>Secrets go here</title>
<description>Secrets go here</description>
<item>
  <title>Secrets go here</title>
  <description>Secrets go here</description>
</item>
</channel>
</rss>