fix many internal links

Fixed a number of internal links that need to
go to the GitHub site.

Ran `make www` to perform the above.

2020/kurdyukov3/index.html

@@ -386,7 +386,7 @@ code</a> below.</p>
 <h2 id="try">Try:</h2>
 <pre><code>    ./try.sh</code></pre>
 <h2 id="alternate-code">Alternate code:</h2>
-<p>The alternate version, <a href="prog.alt.c">prog.alt.c</a>, has the main code as a macro.</p>
+<p>The alternate version, <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/kurdyukov3/prog.alt.c">prog.alt.c</a>, has the main code as a macro.</p>
 <h3 id="alternate-build">Alternate build:</h3>
 <pre><code>    make alt</code></pre>
 <h3 id="alternate-use">Alternate use:</h3>