C#: CCyclomaticComplexity - Fix `@kind` property.

CCyclomaticComplexity is a metric query, so needs a @kind treemap
instead of @kind table.

csharp/ql/src/Metrics/Callables/CCyclomaticComplexity.ql

@@ -1,7 +1,7 @@
 /**
  * @name Cyclomatic complexity of functions
  * @description Methods with a large number of possible execution paths might be difficult to understand.
- * @kind table
+ * @kind treemap
  * @treemap.warnOn highValues
  * @metricType callable
  * @metricAggregate avg max sum