improve display_via_github and display_as values

Fixed some inconsistent use of display_via_github and display_as values.

2004/sds/index.html

@@ -233,7 +233,7 @@ GNU C.</p>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2004/sds/Makefile">Makefile</a> - entry Makefile</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2004/sds/sds.orig.c">sds.orig.c</a> - original source</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2004/sds/try.sh">try.sh</a> - how to run</li>
-<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2004/sds/README_sds.txt">README_sds.txt</a> - sample data used by try.sh</li>
+<li><a href="README_sds.txt">README_sds.txt</a> - sample data used by try.sh</li>
 </ul>
 <h2 id="secondary-files">Secondary files</h2>
 <ul>