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.

2018/yang/.entry.json

@@ -51,7 +51,7 @@
 	},
 	{
 	    "file_path" : "2018_yang.tar.bz2",
-	    "inventory_order" : 100000,
+	    "inventory_order" : 1415926535,
 	    "OK_to_edit" : false,
 	    "display_as" : "tbz2",
 	    "display_via_github" : false,

2018/yang/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>
@@ -141,15 +142,15 @@ Location: <a href="../../location.html#US">US</a> - <em>United States of America
 <!-- 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</code></pre>
+<pre><code>    make</code></pre>
 <h2 id="to-use">To use:</h2>
 <p>The author suggested that after compilation one should look at the generated
 files. For instance:</p>
-<pre class="&lt;!---sh--&gt;"><code>    less generated1.c
+<pre><code>    less generated1.c
     less generated2.c
     less generated3.c</code></pre>
 <h2 id="try">Try:</h2>
-<pre class="&lt;!---sh--&gt;"><code>    ./try.sh</code></pre>
+<pre><code>    ./try.sh</code></pre>
 <h2 id="judges-remarks">Judges’ remarks:</h2>
 <p>Code should be readable in any direction! This tool will help you rotate your
 code so you don’t have to stare at it sideways or even upside down. Rotating
@@ -164,19 +165,19 @@ reveal messages and one more tool that can be used to reveal the final message
 hidden in the original source. All of these can be created using combinations
 of <code>./left</code>, <code>./right</code> and <code>./shift</code> and the additionally generated programs.</p>
 <p>The final message can be revealed using</p>
-<pre class="&lt;!---sh--&gt;"><code>    ./msg9 &lt; prog.c</code></pre>
+<pre><code>    ./msg9 &lt; prog.c</code></pre>
 <p>But what combinations will generate <code>./msg3</code>, <code>./msg4</code>, <code>./msg5</code>, <code>./msg6</code>,
 <code>./msg7</code>, <code>./msg8</code> and finally <code>./msg9</code>?</p>
 <h2 id="authors-remarks">Author’s remarks:</h2>
 <h3 id="tools-usage">Tools’ usage:</h3>
 <p><code>Nuko</code> is a text rotator: given some text in <code>stdin</code>, <code>Nuko</code> will write the
 same text to <code>stdout</code>, but rotated 90 degrees counterclockwise.</p>
-<pre class="&lt;!---sh--&gt;"><code>    cc prog.c -o left
+<pre><code>    cc prog.c -o left
     ./left &lt; input.txt &gt; rotated_counterclockwise.txt</code></pre>
 <p>Due to static memory allocation, only the first 1K columns by 1K rows
 are rotated, the rest are silently ignored. But fear not, a separate
 tool with dynamic memory allocation is included:</p>
-<pre class="&lt;!---sh--&gt;"><code>    ./left &lt; prog.c &gt; r1.c
+<pre><code>    ./left &lt; prog.c &gt; r1.c
     cc r1.c -o right
     ./right &lt; input.txt &gt; rotated_clockwise.txt</code></pre>
 <p>For variety, this second tool rotates clockwise instead of
@@ -186,12 +187,12 @@ depending on how much memory you have.</p>
 rotate counterclockwise once more, we get another program. This
 program outputs a single message to <code>stdout</code>, which is the name of the
 series that <code>Nuko</code> came from.</p>
-<pre class="&lt;!---sh--&gt;"><code>    ./left &lt; prog.c | ./left &gt; r2.c
+<pre><code>    ./left &lt; prog.c | ./left &gt; r2.c
     cc r2.c -o msg0
     ./msg0</code></pre>
 <p>There is one final rotation, which produces a tool that removes
 leading whitespaces:</p>
-<pre class="&lt;!---sh--&gt;"><code>    ./left &lt; prog.c | ./left | ./left &gt; r3.c
+<pre><code>    ./left &lt; prog.c | ./left | ./left &gt; r3.c
     cc r3.c -o shift
     ./shift &lt; input.txt &gt; no_leading_space.txt</code></pre>
 <p>Where this might be useful, besides ruining the formatting of certain
@@ -204,7 +205,7 @@ toward one of those notches (and create a new notch on the other
 side). This shifted code behaves slightly different from the original
 program. For example, here are two more messages that can be
 produced:</p>
-<pre class="&lt;!---sh--&gt;"><code>    ./shift &lt; prog.c | ./right &gt; msg1.c &amp;&amp; gcc msg1.c -o msg1 &amp;&amp; ./msg1
+<pre><code>    ./shift &lt; prog.c | ./right &gt; msg1.c &amp;&amp; gcc msg1.c -o msg1 &amp;&amp; ./msg1
     ./shift &lt; prog.c | ./left &gt; msg2.c &amp;&amp; gcc msg2.c -o msg2 &amp;&amp; ./msg2</code></pre>
 <p>In total, there are 9 embedded strings that can be produced via a
 sequence of rotates and shifts, one of which can be used to extract
@@ -276,10 +277,10 @@ will look weird after rotation, for example.</p>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2018/yang/prog.orig.c">prog.orig.c</a> - original source</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2018/yang/try.sh">try.sh</a> - how to run</li>
 <li><a href="spoiler.html">spoiler.html</a> - SPOILER WARNING</li>
-<li><a href="2018_yang.tar.bz2">2018_yang.tar.bz2</a> - download entry tarball</li>
 </ul>
 <h2 id="secondary-files">Secondary files</h2>
 <ul>
+<li><a href="2018_yang.tar.bz2">2018_yang.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/2018/yang/README.md">README.md</a> - markdown source for this web page</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2018/yang/.entry.json">.entry.json</a> - description of entry in JSON</li>