Rename 2020/ferguson1/deobfuscation -> obfuscation

As the file is not actually code and does not give deobfuscated code but
rather shows how I obfuscated it (indirectly and directly) a better
name, if spoilers will not work, is obfuscation. Thus obfuscation.md and
obfuscation.html are the new names.

Manifest updated; regenerated .entry.json, index.html and other html
files that link to the html file.

In a heading/section (in obfuscation.html) I linked to two files that
are named.

2020/ferguson1/bugs.md

@@ -294,7 +294,7 @@ a bug and I prefer putting in restrictions to try and make it very unlikely.
 [gameplay.html]: gameplay.html
 [cannibalism.log.html]: cannibalism.log.html
 [https://en.wikipedia.org/wiki/Halfwidth_and_fullwidth_forms]: https://en.wikipedia.org/wiki/Halfwidth_and_fullwidth_forms
-[deobfuscation.html]: deobfuscation.html
+[obfuscation.html]: obfuscation.html
 
 
 <hr style="width:10%;text-align:left;margin-left:0">