add rules, guidelines, fix HTML code, move compressed tarball in inventory

By changing the _inventory_order_ of the compressed tarball from
**100000** to **1415926535**, the compressed tarball will land at
the top of the secondary file list and remain still easy to find.

Updated the `manifest.numbers` spreadsheet and rebuilt
the `.entry.json` files.

Added `next/` directory to hold the next IOCCC rules and guidelines.
Added `next/README.md` that `bin/gen-top-html.sh` uses to form
the `next/index.html` file.

Added _Rules and Guidelines_ link to the sidenav bar to link to the
`next/index.html` file.

Added _IOCCC Rules_ as `next/rules.md` that `bin/gen-top-html.sh`
uses to form the `next/rules.html` file.

Added _IOCCC Guidelines_ as `next/guidelines.md` that `bin/gen-top-html.sh`
uses to form the `next/guidelines.html` file.

Changed `bin/gen-top-html.sh` VERSION from "1.2.4 2024-04-13"
to "1.3 2024-04-14".

Prevent `pandoc(1)` from interpreting the commented out language
of a markdown code block as a code class.  So a markdown such as:

````
``` <!---sh-->
...
```
````

that produced HTML of the form:

```html
<pre class="&lt;!---sh--&gt;"><code>...</code></pre>
```

will now produce HTML of the form:

```html
<pre><code>...</code></pre>
```

NOTE: Before when the language of a markdown code block
was not commented, the HTML produced by `pandoc(1)` was
oddly indented with extra whitespace on the first line
of the code block.  While commenting out the language
of the code block removed some of the odd intending,
it left a weird class in the HTML pre block that
surrounded the HTML code block.  This hack prevents
`pandoc(1)` from assigning a class to the HTML pre block.

Changed `in/md2html.sh` VERSION from "1.2.1 2024-04-13"
to "1.3 2024-04-14".

Added `make gen_sitemap` to end of both `make www` and `make
quick_www` in top level Makefile.

Ram `make www` to test under macOS and to perform the above.

**IMPORTANT NOTE**: The current `next/rules.md` and `next/guidelines.md`
are simply the 2020 IOCCC Rules and Guidelines converted into
markdown form.  There are **NOT** the Rules and Guidelines that
will be used the IOCCC MOCK, nor the next IOCCC.

TODO: Improve the `bin/gen-status.sh` tool to modify the top of the
      `next/rules.md` and `next/guidelines.md` files to keep them
      in sync with the _contest_status_ as found in `status.json`.

TODO: Improve the look and feel of the `next/rules.md` and
      `next/guidelines.md` markdown files.

2013/hou/.entry.json

@@ -91,7 +91,7 @@
 	},
 	{
 	    "file_path" : "2013_hou.tar.bz2",
-	    "inventory_order" : 100000,
+	    "inventory_order" : 1415926535,
 	    "OK_to_edit" : false,
 	    "display_as" : "tbz2",
 	    "display_via_github" : false,

2013/hou/doc/example.html

@@ -83,6 +83,7 @@
     <div class="sidenav">
       <a href="../../../news.html">IOCCC News</a>
       <a href="../../../status.html">Contest status</a>
+      <a href="../../../next/index.html">Rules and Guidelines</a>
       <a href="../../../faq.html#submit">How to enter the IOCCC</a>
       <a href="../../../faq.html">FAQ</a>
     </div>

2013/hou/index.html

@@ -88,6 +88,7 @@
     <div class="sidenav">
       <a href="../../news.html">IOCCC News</a>
       <a href="../../status.html">Contest status</a>
+      <a href="../../next/index.html">Rules and Guidelines</a>
       <a href="../../faq.html#submit">How to enter the IOCCC</a>
       <a href="../../faq.html">FAQ</a>
     </div>
@@ -141,18 +142,18 @@ Location: <a href="../../location.html#CN">CN</a> - <em>People’s Republic of C
 <!-- START: this line starts content for HTML phase 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
 
 <h2 id="to-build">To build:</h2>
-<pre class="&lt;!---sh--&gt;"><code>    make all</code></pre>
+<pre><code>    make all</code></pre>
 <h3 id="bugs-and-misfeatures">Bugs and (Mis)features:</h3>
 <p>The current status of this entry is:</p>
 <pre><code>    STATUS: INABIAF - please **DO NOT** fix</code></pre>
 <p>For more detailed information see <a href="../../bugs.html#2013_hou">2013 hou bugs</a>.</p>
 <h2 id="to-use">To use:</h2>
-<pre class="&lt;!---sh--&gt;"><code>    ./hou [scene-file-name] [options]</code></pre>
+<pre><code>    ./hou [scene-file-name] [options]</code></pre>
 <p>Follow the instructions in <code>stdout</code>, preferably with an auto-refreshing PPM
 image viewer ready. Refresh the image every time the output refreshes, all
 effects should be more or less recognizable when you see 16.</p>
 <h2 id="try">Try:</h2>
-<pre class="&lt;!---sh--&gt;"><code>    ./try.sh</code></pre>
+<pre><code>    ./try.sh</code></pre>
 <p>Try opening the file noted by the program then let the program run a while and
 every so often reopen the file, to see how it changes. The author suggests that
 you leave the program running overnight to see what happens. If however you do
@@ -181,7 +182,7 @@ program.</p>
 <a href="https://en.wikipedia.org/wiki/Ray_tracing_(graphics)">raytraced</a> image.</p>
 <p>NOTE: the author refers to <a href="a.c">a.c</a>, placed in a gzipped file <code>a.c.gz</code>. We do not
 include it but it can be generated like:</p>
-<pre class="&lt;!---sh--&gt;"><code>    cc -Wall hou.c -o hou -lm
+<pre><code>    cc -Wall hou.c -o hou -lm
     ./hou &gt; a.c</code></pre>
 <p>but there is no need to do this as the Makefile takes care of it without even
 needing to create a temporary file.</p>
@@ -189,7 +190,7 @@ needing to create a temporary file.</p>
 <h3 id="using-hou">Using hou</h3>
 <p>This program is a programmable rendering engine with a built-in default scene.
 The standard command line is:</p>
-<pre class="&lt;!---sh--&gt;"><code>    ./hou [scene-file-name] [options]</code></pre>
+<pre><code>    ./hou [scene-file-name] [options]</code></pre>
 <p>As <code>hou</code> runs, it writes a progressively refining image to a ppm file specified
 in the scene. The initialization may take a while, but once it’s done, a rough
 preview should be available in seconds. Leave <code>hou</code> running for the night, and you
@@ -363,10 +364,10 @@ frequently found in other <code>PPM</code> implementations.</p></li>
 <li><a href="luna.jpg">luna.jpg</a> - sample image data</li>
 <li><a href="old_default.jpg">old_default.jpg</a> - sample image data</li>
 <li><a href="otherroom.jpg">otherroom.jpg</a> - sample image data</li>
-<li><a href="2013_hou.tar.bz2">2013_hou.tar.bz2</a> - download entry tarball</li>
 </ul>
 <h2 id="secondary-files">Secondary files</h2>
 <ul>
+<li><a href="2013_hou.tar.bz2">2013_hou.tar.bz2</a> - download entry tarball</li>
 <li><a href="index.html">index.html</a> - this web page</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/hou/README.md">README.md</a> - markdown source for this web page</li>
 <li><a href="doc/camera.png">doc/camera.png</a> - documentation support image</li>