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/dorssel/dorssel.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>
@@ -150,7 +151,7 @@ two bits would suffice, e.g.</p>
 <p>That means bits 6 and 5 set to 00 is length 1, set to 01 is length 2, etc.
 But this would mean that we would have to extract the length into a
 counter before shifting out each symbol, such as</p>
-<pre class="&lt;!---c--&gt;"><code>    length = (encoding &amp; 96) &gt;&gt; 5;
+<pre><code>    length = (encoding &amp; 96) &gt;&gt; 5;
     do {
             putchar(encoding &amp; 1 ? &#39;-&#39; : &#39;.&#39;);
             encoding &gt;&gt;= 1;
@@ -162,7 +163,7 @@ counter before shifting out each symbol, such as</p>
     length 4: 00.1xxxx     Z &gt; 00.11100
     length 5: 0.1xxxxx     3 &gt; 0.100111</code></pre>
 <p>with 1 bit still to be chosen freely (let’s assume it is 0). Now we can do</p>
-<pre class="&lt;!---c--&gt;"><code>    do {
+<pre><code>    do {
             putchar(encoding &amp; 1 ? &#39;-&#39; : &#39;.&#39;);
             encoding &gt;&gt;= 1;
     while (encoding &gt; 1);</code></pre>
@@ -179,7 +180,7 @@ following</p>
 <p>Notice these encodings in the initialization string. Only the coding for
 <code>5</code> needs an escape (<code>5 = ..... &gt; 01111111 = '\177'</code>). The way the length
 is encoded still allows the encoding to be its own counter:</p>
-<pre class="&lt;!---c--&gt;"><code>    do {
+<pre><code>    do {
             putchar(encoding &amp; 1 ? &#39;-&#39; : &#39;.&#39;);
             encoding = (encoding + 32) &gt;&gt; 1;
     } while (encoding &gt; 35);</code></pre>
@@ -188,12 +189,12 @@ Note that the calculation for the next value of <code>encoding</code> is done at
 precision, so that the actual value of the <code>char</code> remains <code>&lt;= 127</code>.</p>
 <p>The character <code>'-'</code> (ASCII 45) and <code>'.'</code> (ASCII 46) are conveniently in
 sequence, so the putchar can simply be</p>
-<pre class="&lt;!---c--&gt;"><code>    putchar(45 + encoding % 2);</code></pre>
+<pre><code>    putchar(45 + encoding % 2);</code></pre>
 <p>I used the modulo operator this time, because <code>+</code> takes precedence over <code>&amp;</code>.
 The assignment can be incorporated into the <code>while</code> control test, and a
 <code>do-while</code> loop with a body of a single expression statement can be written
 as a <code>while</code> loop with a comma operator in the test:</p>
-<pre class="&lt;!---c--&gt;"><code>    while(putchar(45 + encoding % 2), encoding = encoding + 32 &gt;&gt; 1);</code></pre>
+<pre><code>    while(putchar(45 + encoding % 2), encoding = encoding + 32 &gt;&gt; 1);</code></pre>
 <p>Voila.</p>
 <p>Now, the decoding of Morse codes is just the reverse. We shift in <code>0</code>s
 and <code>1</code>s as we scan the line. But: we have to scan from back to front