convert spoiler filenames into deobfuscation filenames

2019/yang/index.html

@@ -424,6 +424,8 @@ Location: <a href="../../location.html#US">US</a> - <em>United States of America
 <h2 id="judges-remarks">Judges’ remarks:</h2>
 <p>Do you understand how this program works? You may have to go over and over the
 output again.</p>
+<p>If you run into difficultly in understanding the code, you may wish
+to review the <a href="deobfuscation.html">deobfuscation.html</a> web page.</p>
 <h2 id="authors-remarks">Author’s remarks:</h2>
 <h3 id="summary">Summary:</h3>
 <p>Scramble/unscramble to single file:</p>
@@ -557,7 +559,7 @@ the same name, the character who is highly skilled in writing letters.</p>
 <li><a href="sample_input.txt">sample_input.txt</a> - sample input</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2019/yang/try.sh">try.sh</a> - script to try entry</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2019/yang/violet.c">violet.c</a> - source formatter as ASCII Violet Evergarden</li>
-<li><a href="spoiler.html">spoiler.html</a> - spoiler web page</li>
+<li><a href="deobfuscation.html">deobfuscation.html</a> - Deobfuscation information web page</li>
 </ul>
 <h2 id="secondary-files">Secondary files</h2>
 <ul>