improve display_via_github and display_as values

Fixed some inconsistent use of display_via_github and display_as values.

2019/karns/index.html

@@ -230,7 +230,7 @@ not encountered this myself).</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2019/karns/prog.c">prog.c</a> - entry source</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2019/karns/Makefile">Makefile</a> - entry Makefile</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2019/karns/prog.orig.c">prog.orig.c</a> - original source</li>
-<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2019/karns/maze">maze</a> - input maze map</li>
+<li><a href="maze">maze</a> - input maze map</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2019/karns/try.sh">try.sh</a> - how to run</li>
 </ul>
 <h2 id="secondary-files">Secondary files</h2>