Reword the recent deobfuscation changes

In most cases the word was changed to 'obfuscation' as it was about
obfuscation, not deobfuscation. In some cases like 1995/leo since the
file was (in 1995/leo) about a secret switch it was changed to
'secret.md' (and 'secret.html') but there were others like that as well.

One entry had the words 'spoiling the size rule' but this had been
changed to 'deobfuscating the size rule' which was obviously wrong.

In the latter YYYY/README.md files the judges had written after some
entries (brief summaries) '...

    ...We'll stop spouting spoilers now. Have fun exploring all the
    entries!

but that was changed to:

    ...We'll stop spouting deobfuscation information now. Have fun
    exploring all the entries!

which wasn't really about deobfuscation but just a brief summary of what
the entries did.

And in the most problematic case (at least for me :-), 2018/ferguson) I
had put a joke in:

    ... but it's the only Easter egg I won't spoil

but it was changed to 'won't deobfuscate' which not only is not what it
is but it spoilt the joke.

In some cases the word was changed back to 'SPOILER' (or similar) but in
most cases not. I believe it should be better now. There are some
caveats, however, as below.

Although make find_missing_links is okay I do not remember if this will
catch links that refer to '%%REPO_URL%%' or other pandoc tokens. This
means I might have to go back to some earlier years to verify links are
okay. That should not take that much time I hope.

It might also be that some wording can still be improved some but it is
hoped this will be discovered when checking links and looking over the
manifest (which obviously changed).

2005/anon/README.md

@@ -12,7 +12,8 @@ version](#alternate-code) below. If your terminal has problems with the
     make anon-no_stty
 ```
 
-This will compile [anon.c](%%REPO_URL%%/2005/anon/anon.c) as `anon` to not use `stty(1)`.
+This will compile [anon.c](%%REPO_URL%%/2005/anon/anon.c) as `anon` to not use
+`stty(1)`, with the support of an `#ifdef..#endif` added by the author.
 
 
 ### Bugs and (Mis)features:
@@ -202,7 +203,7 @@ hit enter after every key), but it works.
 The game requires lots of space on the runtime stack space due to deep
 recursion, among other things. :-)
 
-See the "**DEOBFUSCATION**" section below for more notes about portability.
+See the "**OBFUSCATION**" section below for more notes about portability.
 
 
 ### ABOUT THE CODE
@@ -280,7 +281,7 @@ It probably will also compile and work on many (all?) other \*nix platforms as
 well. How does it achieve this incredible feat?
 
 
-### DEOBFUSCATION
+### OBFUSCATION
 
 Read the following only if you give up figuring it out :-)
 

2005/anon/index.html

@@ -407,7 +407,8 @@ Location: <a href="../../location.html#ZZ">ZZ</a> - <em>Unknown location</em></l
 version</a> below. If your terminal has problems with the
 <code>stty(1)</code> commands try:</p>
 <pre><code>    make anon-no_stty</code></pre>
-<p>This will compile <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2005/anon/anon.c">anon.c</a> as <code>anon</code> to not use <code>stty(1)</code>.</p>
+<p>This will compile <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2005/anon/anon.c">anon.c</a> as <code>anon</code> to not use
+<code>stty(1)</code>, with the support of an <code>#ifdef..#endif</code> added by the author.</p>
 <h3 id="bugs-and-misfeatures">Bugs and (Mis)features:</h3>
 <p>The current status of this entry is:</p>
 <pre><code>    STATUS: INABIAF - please DO NOT fix</code></pre>
@@ -514,7 +515,7 @@ with <code>-DNO_STTY</code>. The game interface will be a bit annoying (you will
 hit enter after every key), but it works.</p>
 <p>The game requires lots of space on the runtime stack space due to deep
 recursion, among other things. :-)</p>
-<p>See the “<strong>DEOBFUSCATION</strong>” section below for more notes about portability.</p>
+<p>See the “<strong>OBFUSCATION</strong>” section below for more notes about portability.</p>
 <h3 id="about-the-code">ABOUT THE CODE</h3>
 <p>Clearly, the author is very, very confused. Although he has broken up the file
 into sections labelled with helpful headings, and although he has left ample
@@ -577,7 +578,7 @@ on the following architectures:</p>
 </ul>
 <p>It probably will also compile and work on many (all?) other *nix platforms as
 well. How does it achieve this incredible feat?</p>
-<h3 id="deobfuscation">DEOBFUSCATION</h3>
+<h3 id="obfuscation">OBFUSCATION</h3>
 <p>Read the following only if you give up figuring it out :-)</p>
 <h4 id="the-evil-hack">The Evil Hack</h4>
 <p>The program (ab)uses an implicit assumption underlying practically all