Update invalid link to devx.com

Author: sidshank

java/ql/src/Metrics/Files/FNumberOfClasses.qhelp

@@ -100,7 +100,7 @@ to enumerations.
 
 
 <li>
-H. Kabutz. <a href="http://www.devx.com/Java/Article/10686">Java History 101: Once Upon an Oak</a>. Published online.
+H. Kabutz. <a href="https://www.devx.com/java-zone/10686/">Java History 101: Once Upon an Oak</a>. Published online.
 </li>