Fix remaining broken links in 2013/hou

Now the tool bin/find-missing-links.sh exits 0!

2013/hou/index.html

@@ -494,7 +494,7 @@ restrictions</a> section below for more details.</li>
 <ul>
 <li>The building process does not involve any OS tool beyond <code>cc(1)</code> and
 <code>make(1)</code>. No <code>gzip(1)</code> compression! <code>a.c.gz</code> doesn’t fit in 2053 bytes, anyway.</li>
-<li>Neither <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/hou/hou.c">hou.c</a> nor <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/hou/a.c">a.c</a> (the <em>real</em> decompressed source) uses
+<li>Neither <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/hou/hou.c">hou.c</a> nor <code>a.c</code> (the <em>real</em> decompressed source) uses
 <code>#define</code> (or <code>cc -D</code>) at all.</li>
 <li>The source code is not required at runtime.</li>
 <li><code>a.c</code> does not drop optional features to reduce size. There are pure