convert spoiler language and towards deobfuscation language

1993/plummer/README.md

@@ -125,7 +125,7 @@ compilers) complain that there is no control path leading to a return from
 `main()`.  At 125 characters, it still fits on a single line (for those of us
 who don't mind ruining our eyes with 132 column screens).
 
-### Spoiler:
+### Deobfuscation:
 
 The first statement points the base of `l` (the argument vector) to
 be the first argument by incrementing it.  It then assigns `O` to

1993/plummer/index.html

@@ -481,7 +481,7 @@ return causes the line just written to be overwritten. <code>lint</code> (and mo
 compilers) complain that there is no control path leading to a return from
 <code>main()</code>. At 125 characters, it still fits on a single line (for those of us
 who don’t mind ruining our eyes with 132 column screens).</p>
-<h3 id="spoiler">Spoiler:</h3>
+<h3 id="deobfuscation">Deobfuscation:</h3>
 <p>The first statement points the base of <code>l</code> (the argument vector) to
 be the first argument by incrementing it. It then assigns <code>O</code> to
 point to the character before the first character of the second