Add helpful image to 2020/ferguson1

.. at least helpful to those doing a special thing :-)

Updated .entry.json and rebuilt respective html files.

2020/ferguson1/index.html

@@ -975,6 +975,7 @@ email but I’m more likely to respond to mastodon messages.</p>
 <li><a href="https://github.com/ioccc-src/winner/blob/master/2020/ferguson1/README.md">README.md</a> - markdown source for this web page</li>
 <li><a href="https://github.com/ioccc-src/winner/blob/master/2020/ferguson1/bugs.md">bugs.md</a> - markdown source for bugs.html</li>
 <li><a href="cake.jpg">cake.jpg</a> - image of Double-layered Chocolate Fudge Cake</li>
+<li><a href="cake-on-cooling-rack.jpg">cake-on-cooling-rack.jpg</a> - Double-layered Chocolate Fudge Cake on cooling rack</li>
 <li><a href="https://github.com/ioccc-src/winner/blob/master/2020/ferguson1/cannibalism.log.md">cannibalism.log.md</a> - markdown source for cannibalism.log.html</li>
 <li><a href="https://github.com/ioccc-src/winner/blob/master/2020/ferguson1/chocolate-cake.md">chocolate-cake.md</a> - markdown source for chocolate-cake.html</li>
 <li><a href="https://github.com/ioccc-src/winner/blob/master/2020/ferguson1/crazy.log.md">crazy.log.md</a> - markdown source for crazy.log.html</li>