Fix mismatched tags in Javadoc.

Change-Id: If71abf90a2b924707b26ef4bee962db5a964a49b
Reviewed-on: http://gerrit.dmdirc.com/3442
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Greg Holmes <greg@dmdirc.com>

src/com/dmdirc/config/prefs/reader/CategoryReader.java

@@ -52,7 +52,7 @@ import static com.google.common.base.Preconditions.checkNotNull;
  *     items:
  *       - [item]
  *       - [item]
- * </pre></code>
+ * </code></pre>
  */
 public class CategoryReader {