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/ferguson2/index.html

@@ -965,9 +965,9 @@ https://creativecommons.org/licenses/by-sa/4.0/</p>
 
 <h1 id="inventory-for-2020ferguson2"><a name="inventory"></a>Inventory
 for 2020/ferguson2</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/ferguson2/prog.c">prog.c</a>
 - entry source</li>
@@ -980,15 +980,21 @@ href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson2/pr
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson2/prog.orig.c">prog.orig.c</a>
 - original source</li>
+<li><a href="chocolate-cake.html">chocolate-cake.html</a> - encrypted
+chocolate cake recipe</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson2/input.txt">input.txt</a>
 - sample input</li>
+<li><a href="obfuscation.html">obfuscation.html</a> - about the
+obfuscation of this entry</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson2/obfuscation.txt">obfuscation.txt</a>
 - sample input</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson2/recode.c">recode.c</a>
 - Enigma machine simulato source code</li>
+<li><a href="recode.html">recode.html</a> - recode configurator
+documentation</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson2/try.alt.sh">try.alt.sh</a>
 - how to run alternative code</li>
@@ -1015,6 +1021,7 @@ 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/ferguson2/.entry.json">.entry.json</a>
 - description of entry in JSON</li>
@@ -1028,7 +1035,7 @@ href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson2/RE
 <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/ferguson2/chocolate-cake.md">chocolate-cake.md</a>
-- markdown source for COMPILING.html</li>
+- markdown source for chocolate-cake.html</li>
 <li><a href="ioccc-cake.jpg">ioccc-cake.jpg</a> - image for chocolate
 cake</li>
 <li><a
@@ -1036,7 +1043,7 @@ href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson2/ob
 - markdown source for obfuscation.html</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/ferguson2/recode.md">recode.md</a>
-- markdown source for index.html</li>
+- markdown source for recode.html</li>
 </ul>
 
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