improve display_via_github and display_as values

Fixed some inconsistent use of display_via_github and display_as values.

1998/tomtorfs/index.html

@@ -245,7 +245,7 @@ for writing this. You can find it in <a href="crc.txt">crc.txt</a>.</p>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1998/tomtorfs/Makefile">Makefile</a> - entry Makefile</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1998/tomtorfs/tomtorfs.orig.c">tomtorfs.orig.c</a> - original source</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1998/tomtorfs/try.sh">try.sh</a> - how to run</li>
-<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1998/tomtorfs/crc.txt">crc.txt</a> - painless guide to CRC algorithms</li>
+<li><a href="crc.txt">crc.txt</a> - painless guide to CRC algorithms</li>
 </ul>
 <h2 id="secondary-files">Secondary files</h2>
 <ul>