convert spoiler language and towards deobfuscation language

1990/dg/README.md

@@ -43,7 +43,7 @@ which we have done for the wider audience.
 If my preprocessor could hack it, I could write this as one single line rather
 than 4, but when I do that I get a complaint "defines nested too deeply".
 
-### Obfuscation spoiler:
+### Debfuscation:
 
 This is another rot13 job (believe it or not) - the `#define`s are a
 novel way of adding tokens: `#define b12(x) 12 x` means that at

1990/dg/index.html

@@ -418,7 +418,7 @@ which we have done for the wider audience.</p>
 <h2 id="authors-remarks">Author’s remarks:</h2>
 <p>If my preprocessor could hack it, I could write this as one single line rather
 than 4, but when I do that I get a complaint “defines nested too deeply”.</p>
-<h3 id="obfuscation-spoiler">Obfuscation spoiler:</h3>
+<h3 id="debfuscation">Debfuscation:</h3>
 <p>This is another rot13 job (believe it or not) - the <code>#define</code>s are a
 novel way of adding tokens: <code>#define b12(x) 12 x</code> means that at
 some point in the source a <code>12</code> is followed by the compressed nested