Fix remaining broken links in 2013/hou

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

2013/hou/README.md

@@ -147,7 +147,7 @@ restrictions](#self-imposed-restrictions) section below for more details.
 
 * The building process does not involve any OS tool beyond `cc(1)` and
 `make(1)`. No `gzip(1)` compression! `a.c.gz` doesn't fit in 2053 bytes, anyway.
-* Neither [hou.c](%%REPO_URL%%/2013/hou/hou.c) nor [a.c](%%REPO_URL%%/2013/hou/a.c) (the *real* decompressed source) uses
+* Neither [hou.c](%%REPO_URL%%/2013/hou/hou.c) nor `a.c` (the *real* decompressed source) uses
 `#define` (or `cc -D`) at all.
 * The source code is not required at runtime.
 * `a.c` does not drop optional features to reduce size. There are pure

2013/hou/doc/example.html

@@ -605,7 +605,7 @@ editing program, you need to convert the RGB values from 0..255 to 0..1, and
 then put here its <em>square</em>. Only after squaring you get your real, lively color
 in the output image, as opposed to something dull and gray. You need to do the
 same if you use a RGB texture. And yes, that is the what the second <code>sqrt(3)</code> in
-<a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/hou/a.c">a.c</a> is for.</p>
+<code>a.c</code> is for.</p>
 <p>Going beyond colors, to define a shiny or dull surface one needs more maths, and
 optics. The jargon for this is <code>BRDF</code> (Bidirectional Reflectance Distribution
 Function) importance sampling. Let’s continue to function <code>o</code>.</p>

2013/hou/doc/example.md

@@ -312,7 +312,7 @@ editing program, you need to convert the RGB values from 0..255 to 0..1, and
 then put here its *square*. Only after squaring you get your real, lively color
 in the output image, as opposed to something dull and gray. You need to do the
 same if you use a RGB texture. And yes, that is the what the second `sqrt(3)` in
-[a.c](%%REPO_URL%%/2013/hou/a.c) is for.
+`a.c` is for.
 
 Going beyond colors, to define a shiny or dull surface one needs more maths, and
 optics. The jargon for this is `BRDF` (Bidirectional Reflectance Distribution

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