fix markdown footnote problem caused by pandoc

Add "<!-- BEFORE: 1st line of markdown file: FILE/PATH -->"
before the markdown content.  This line appears in the
generated HTML.

Add "<!-- AFTER: last line of markdown file: FILE/PATH -->"
after the markdown content.  This line appears in the
generated HTML.

We test a fix relating to problems produced by `pandoc(1)`
when footnotes are added at the end of generated HTML.
This test is made for `2000/bmeyer/index.html`.

Fixed exit 4 in `bin/md2html.sh that should be exit 5.

Changed `bin/md2html.sh` VERSION from to "1.3 2024-04-14"
to "1.4 2024-04-18".

Run `bin/readme2index.sh -v 1 2000/bmeyer` to perform the above.

2015/endoh1/index.html

@@ -156,6 +156,7 @@ Location: <a href="../../location.html#JP">JP</a> - <em>Japan</em></li>
 <!-- END: this line ends content for HTML phase 20 by: bin/output-index-author.sh via bin/md2html.sh -->
 <!-- START: this line starts content for HTML phase 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
 
+<!-- BEFORE: 1st line of markdown file: 2015/endoh1/README.md -->
 <h2 id="to-build">To build:</h2>
 <pre><code>    make</code></pre>
 <p>NOTE: this program requires the tool <code>tcpserver</code> to use. If you do not have this
@@ -310,8 +311,10 @@ field data to the browser on each frame.</li>
         https://creativecommons.org/licenses/by-sa/4.0/
 
 -->
+<!-- AFTER: last line of markdown file: 2015/endoh1/README.md -->
+<hr style="width:10%;text-align:left;margin-left:0">
 <section id="footnotes" class="footnotes footnotes-end-of-document" role="doc-endnotes">
-<hr />
+<h5>Footnotes</h5>
 <ol>
 <li id="fn1"><p>Turing, A. M., “The Chemical Basis of Morphogenesis”, Philosophical Transactions of the Royal Society, 1952.<a href="#fnref1" class="footnote-back" role="doc-backlink">↩︎</a></p></li>
 <li id="fn2"><p>The Ready Bunch, “Ready”, A cross-platform implementation of various reaction-diffusion systems, since 2011, <a href="https://github.com/GollyGang/ready" class="uri">https://github.com/GollyGang/ready</a>.<a href="#fnref2" class="footnote-back" role="doc-backlink">↩︎</a></p></li>