fix links in entry HTML files other than index.html

Fixed internal links in entry HTML files other than index.html.

Removed links to markdown files that otherwise used to
generate HTML files other than index.html.

Ran `make gen_other_html` to perform the above.

2020/ferguson1/chocolate-cake.html

@@ -140,7 +140,7 @@ something of my mum’s speciality. It’s complicated and I should warn that no
 has seemed to get it down as well as she has but it’s well worth the effort if
 you love chocolate and have the time and patience.</p>
 <p>My late stepmum who only liked white ‘chocolate’ loved this cake! The picture
-below is after it’s been iced. The image <a href="ioccc-cake.jpg">ioccc-cake.jpg</a> was a
+below is after it’s been iced. The image <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/cake.jpg">cake.jpg</a> was a
 feeble attempt at drawing <code>IOCCC</code> into the cake before icing, a different time.
 The picture below was taken for my birthday (14 February) in 2022 as it’s the
 best one I have:</p>
@@ -161,9 +161,9 @@ there of course. Please make sure to mention me so I get a push notification as
 I don’t check it very often. Thanks and again enjoy!</p>
 <h2 id="measurements">Measurements</h2>
 <p>This was originally taken from an American magazine for women so the
-measurements are in the US standards. A nice resource (that has much more than
-just cooking) is <a href="http://www.onlineconversion.com/cooking.htm" class="uri">http://www.onlineconversion.com/cooking.htm</a>. This will
-particularly matter for cups, teaspoons, tablespoons and ounces.</p>
+measurements are in the US standards. There is a
+<a href="http://www.onlineconversion.com/cooking.htm">nice resource</a> that has much more than
+just cooking). This will particularly matter for cups, teaspoons, tablespoons and ounces.</p>
 <h2 id="bakers-chocolate">Baker’s chocolate</h2>
 <p>Baker’s chocolate is a brand name and the product in question is unsweetened
 chocolate bars used for baking. According to a <a href="https://www.davidlebovitz.com/chocolate-faqs/">chocolates FAQ</a> it might be