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`.

2020/ferguson1/index.html

@@ -737,9 +737,9 @@ https://creativecommons.org/licenses/by-sa/4.0/</p>
 
 <h1 id="inventory-for-2020ferguson1"><a name="inventory"></a>Inventory
 for 2020/ferguson1</h1>
+<p><a href="#top">Jump to top</a></p>
 <h2 id="primary-files">Primary files</h2>
 <ul>
-<li><a href="index.html">index.html</a> - entry home page</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/prog.c">prog.c</a>
 - entry source</li>
@@ -755,16 +755,28 @@ href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/pr
 <li><a href="COMPILING.html">COMPILING.html</a> - about compiling</li>
 <li><a href="HACKING.html">HACKING.html</a> - information for
 herpetologist hackers</li>
+<li><a href="bugs.html">bugs.html</a> - current bugs and things that
+look like bugs but are not</li>
 <li><a href="cannibalism.log.html">cannibalism.log.html</a> - about the
 snake game</li>
+<li><a href="chocolate-cake.html">chocolate-cake.html</a> -
+double-layered chocolate fudge cake recipe</li>
 <li><a href="crazy.log.html">crazy.log.html</a> - about some screen
 dumps</li>
+<li><a href="gameplay.html">gameplay.html</a> - how to play the
+game</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/play.sh">play.sh</a>
 - how to run</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/snake-colours.sh">snake-colours.sh</a>
 - script to reset - preset colors</li>
+<li><a href="spoilers.html">spoilers.html</a> - SPOILER ALERT - about
+the code</li>
+<li><a href="terminals.html">terminals.html</a> - terminal capabilities
+and dimensions and colors</li>
+<li><a href="troubleshooting.html">troubleshooting.html</a> -
+troubleshooting the game</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/prog.2.c">prog.2.c</a>
 - source with more digraphs</li>
@@ -785,6 +797,7 @@ download entry source</li>
 </ul>
 <h2 id="secondary-files">Secondary files</h2>
 <ul>
+<li><a href="index.html">index.html</a> - entry home page</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/.entry.json">.entry.json</a>
 - description of entry in JSON</li>
@@ -794,7 +807,7 @@ href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/.g
 <li><a href=".path">.path</a> - directory path from top directory</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/COMPILING.md">COMPILING.md</a>
-- markdown source for crazy.log.html</li>
+- markdown source for COMPILING.html</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/HACKING.md">HACKING.md</a>
 - markdown source for HACKING.html</li>
@@ -807,13 +820,13 @@ href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/bu
 <li><a href="cake.jpg">cake.jpg</a> - image for chocolate cake</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/cannibalism.log.md">cannibalism.log.md</a>
-- markdown source for chocolate-cake.html</li>
+- markdown source for cannibalism.log.html</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/chocolate-cake.md">chocolate-cake.md</a>
 - markdown source for chocolate-cake.html</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/crazy.log.md">crazy.log.md</a>
-- markdown source for deckmyn.html</li>
+- markdown source for crazy.log.html</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson1/gameplay.md">gameplay.md</a>
 - markdown source for gameplay.html</li>