update other entry HTML files

Ran `make gen_other_html` to perform the above.

2020/ferguson2/obfuscation.html

@@ -334,6 +334,8 @@ the other part of the question up to the reader to answer. Hint: you already
 know how it works (yes, really you do)! Another hint: This is and is not a
 misleading comment (conversely this makes this hint both misleading - and
 also not).</p>
+<hr style="width:10%;text-align:left;margin-left:0">
+<p>Jump to: <a href="#">top</a></p>
 <!--
 
     Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.

2020/ferguson2/recode.html

@@ -599,6 +599,8 @@ the key you wish to select is</p>
 <p>you can do:</p>
 <pre><code>    ./recode -R0EZ4PC1CC0PGTAQSOXWNMDRYKFUZEI -fencrypted.html | ./prog - 2&gt;/dev/null &gt; decrypted.html</code></pre>
 <p>Then open <code>decrypted.html</code> in your browser.</p>
+<hr style="width:10%;text-align:left;margin-left:0">
+<p>Jump to: <a href="#">top</a></p>
 <!--
 
     Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.