Consistency and other fixes in manifest

As the index.html/README.md files say 'Alternate code' the 'alternative
source' has been changed to 'alternate code'. Similarly the text 'script
to try alternative code' was changed to 'script to try alternate code'.

A mistake was made where something referred to as being the alt code was
not the alt code (or the other way round).

Changed 'alternate alternative code' (or something like that) to 'second
alternate code'. This happened in steps and it might not, now that I
think on it, be the best wording, but this can be addressed later.

Rebuilt html files and .entry.json files.

2020/kurdyukov3/index.html

@@ -455,10 +455,10 @@ as these letters are encoded in the higher part of the single-byte character set
 <ul>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/kurdyukov3/prog.c">prog.c</a> - entry source</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/kurdyukov3/Makefile">Makefile</a> - entry Makefile</li>
-<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/kurdyukov3/prog.alt.c">prog.alt.c</a> - alternative source</li>
+<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/kurdyukov3/prog.alt.c">prog.alt.c</a> - alternate code</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/kurdyukov3/prog.orig.c">prog.orig.c</a> - original source</li>
 <li><a href="input.txt">input.txt</a> - sample input</li>
-<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/kurdyukov3/prog.extra.c">prog.extra.c</a> - alternative source with extra functionality</li>
+<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/kurdyukov3/prog.extra.c">prog.extra.c</a> - alternate code with extra functionality</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/kurdyukov3/try.sh">try.sh</a> - script to try entry</li>
 </ul>
 <h2 id="secondary-files">Secondary files</h2>