C++: fix HubClasses.ql by changing its kind to 'table'

Author: aibaars

cpp/ql/src/Architecture/General Class-Level Information/HubClasses.ql

@@ -2,7 +2,7 @@
  * @name Hub classes
  * @description Shows coupling between classes. Large, red, boxes are hub types that depend on many other classes
  *              and are depended on by many other classes.
- * @kind treemap
+ * @kind table
  * @id cpp/architecture/hub-classes
  * @treemap.warnOn highValues
  * @tags maintainability