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.

1998/schweikh1/macos.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>
@@ -138,7 +139,7 @@ a file was not found (this limitation was removed in both versions in 2023). see
 <p>However, as noted, macOS does <strong>not</strong> have <code>/usr/include</code> so this would never
 work for macOS without some changes, described next. For macOS you will need the
 command line tools installed which can be done like:</p>
-<pre class="&lt;!---sh--&gt;"><code>    sudo xcode-select --install</code></pre>
+<pre><code>    sudo xcode-select --install</code></pre>
 <p>An important point is that the original version hard-coded <code>gcc</code> but just like
 the entry, the alternate version has also removed this limitation despite <code>gcc</code>
 existing (though it’s <code>clang</code>) in macOS.</p>
@@ -154,7 +155,7 @@ the command is:</p>
 <p>which has been changed to be:</p>
 <pre><code>&quot;0cc -ansi -E -dM -undef %s /usr/include/%s&gt;r\0 (&quot;</code></pre>
 <p>Shortly below that you will see, as noted above, the numbers:</p>
-<pre class="&lt;!---c--&gt;"><code>    if ((H = fopen (__FILE__+43, 43+__FILE__)))
+<pre><code>    if ((H = fopen (__FILE__+43, 43+__FILE__)))
     while ((fgets (L, (int)sizeof L, H)) != 0) {
             I[strcspn (I, 45+__FILE__)] = O = 0;</code></pre>
 <p>The first number in the above C means the length starting from 0 up through the