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/burton/index.html

@@ -151,6 +151,7 @@ Location: <a href="../../location.html#US">US</a> - <em>United States of America
 <!-- 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/burton/README.md -->
 <h2 id="to-build">To build:</h2>
 <pre><code>    make</code></pre>
 <h2 id="to-use">To use:</h2>
@@ -293,6 +294,7 @@ This allows for a convenient test suite:</p>
         https://creativecommons.org/licenses/by-sa/4.0/
 
 -->
+<!-- AFTER: last line of markdown file: 2015/burton/README.md -->
 
 <!-- END: this line ends content for HTML phase 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
 <!-- START: this line starts content for HTML phase 22 by: bin/output-index-inventory.sh via bin/md2html.sh -->

2015/burton/road.to.obscurity.html

@@ -133,6 +133,7 @@
 <!-- END: this line ends content from: inc/before-content.default.html -->
 <!-- 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/burton/road.to.obscurity.md -->
 <h1 id="development-of-the-obfuscated-calculator.">Development of the obfuscated calculator.</h1>
 <p>I wanted to enter the IOCCC….</p>
 <p>I think I can write something clever. Possibly even obscure. The competition
@@ -346,6 +347,7 @@ functionality. Now I think I have a good entry.</p>
         https://creativecommons.org/licenses/by-sa/4.0/
 
 -->
+<!-- AFTER: last line of markdown file: 2015/burton/road.to.obscurity.md -->
 
 <!-- END: this line ends content for HTML phase 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
 <!-- START: this line starts content from: inc/after-content.default.html -->

2015/burton/spoilers.html

@@ -133,6 +133,7 @@
 <!-- END: this line ends content from: inc/before-content.default.html -->
 <!-- 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/burton/spoilers.md -->
 <h3 id="spoilers">Spoilers</h3>
 <p><code>calc</code> is a recursive-descent parser. It allocates from the stack deep enough
 that all expressions are exhausted before the recursion stack depth reaches the
@@ -176,6 +177,7 @@ obfuscation, and remarkably effective.</p>
         https://creativecommons.org/licenses/by-sa/4.0/
 
 -->
+<!-- AFTER: last line of markdown file: 2015/burton/spoilers.md -->
 
 <!-- END: this line ends content for HTML phase 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
 <!-- START: this line starts content from: inc/after-content.default.html -->