build missing HTML files for entries

Setup a simple topnav for missing HTML files for entries.

Added `bin/gen-other-html.sh` to build entry HTML files from
markdown other than README.md to index.html HTML files.

Fixed duplicate link text in `2020/ferguson1/gameplay.md`.

Improved `inc/md2html.cfg` to support building the missing HTML
files for entries.

Added `make gen_other_html` to top level Makefile.
Added `make gen_other_html` to `make quick_www` and `make www`.

Fixed inventory links for year level index.html files.
Changed `bin/output-year-index.sh` VERSION from "1.0.1 2024-02-23"
to "1.1 2024-02-27".

Added missing lines in `manifest.numbers`.  Update the affected
`.entry.json` files.

The manifest (in both `manifest.numbers` and the collection of
manifests from of all entry `.entry.json` files) now match.  Errors
from `make verify_entry_files` will now abort both `make quick_www`
and `make www` rules in the top level `Makefile`.

Changed markdown files in manifest to have an _inventory_order_ of
_2000000000_ so that the `index.html` file will usually appear at
the start of the _Secondary files_ set for the "#inventory" section
of an entry's `index.html` file.

Changed compressed tar files (files that end in _.tar.bz2_) in
manifest to have an _inventory_order_ of _100000_ so that these
files will usually appear at the end of the _Primary files_ set for
the "#inventory" section of an entry's `index.html` file.

Added 'Jump to top` link above the _Primary files_ section.
Changed `bin/output-index-inventory.sh` VERSION from "1.1.1 2024-02-23"
to "1.2 2024-02-27".

Updated HTML files to perform the above via `make www`.

2015/index.html

@@ -223,30 +223,26 @@ Entries of 2015 - The 24th IOCCC</h1>
 <p><strong>Download IOCCC</strong> <a
 href="2015/ioccc.2015.tar.bz2">2015 entry source</a></p>
 <ul>
-<li><a href="2015/burton/index.html">2015/burton</a> - Most Useful</li>
-<li><a href="2015/dogon/index.html">2015/dogon</a> - Most Crafty</li>
-<li><a href="2015/duble/index.html">2015/duble</a> - Best
-Handwriting</li>
-<li><a href="2015/endoh1/index.html">2015/endoh1</a> - Most Diffused
+<li><a href="burton/index.html">2015/burton</a> - Most Useful</li>
+<li><a href="dogon/index.html">2015/dogon</a> - Most Crafty</li>
+<li><a href="duble/index.html">2015/duble</a> - Best Handwriting</li>
+<li><a href="endoh1/index.html">2015/endoh1</a> - Most Diffused
 Reaction</li>
-<li><a href="2015/endoh2/index.html">2015/endoh2</a> - Most Overlooked
+<li><a href="endoh2/index.html">2015/endoh2</a> - Most Overlooked
 Obfuscation</li>
-<li><a href="2015/endoh3/index.html">2015/endoh3</a> - Back to the
-Future Award</li>
-<li><a href="2015/endoh4/index.html">2015/endoh4</a> - Best
-One-liner</li>
-<li><a href="2015/hou/index.html">2015/hou</a> - Most Well-rounded
-Hash</li>
-<li><a href="2015/howe/index.html">2015/howe</a> - Most Different</li>
-<li><a href="2015/mills1/index.html">2015/mills1</a> - For the Birds!
+<li><a href="endoh3/index.html">2015/endoh3</a> - Back to the Future
 Award</li>
-<li><a href="2015/mills2/index.html">2015/mills2</a> - Most Compact</li>
-<li><a href="2015/muth/index.html">2015/muth</a> - Most Complete Use of
+<li><a href="endoh4/index.html">2015/endoh4</a> - Best One-liner</li>
+<li><a href="hou/index.html">2015/hou</a> - Most Well-rounded Hash</li>
+<li><a href="howe/index.html">2015/howe</a> - Most Different</li>
+<li><a href="mills1/index.html">2015/mills1</a> - For the Birds!
+Award</li>
+<li><a href="mills2/index.html">2015/mills2</a> - Most Compact</li>
+<li><a href="muth/index.html">2015/muth</a> - Most Complete Use of
 CPP</li>
-<li><a href="2015/schweikhardt/index.html">2015/schweikhardt</a> - Best
+<li><a href="schweikhardt/index.html">2015/schweikhardt</a> - Best
 Documented</li>
-<li><a href="2015/yang/index.html">2015/yang</a> - Most Pointed
-Reaction</li>
+<li><a href="yang/index.html">2015/yang</a> - Most Pointed Reaction</li>
 </ul>
 <p> <strong>Jump to:</strong> <a href="#">top</a></p>