Swift: header comment for ControlFlowGraphParameter

Author: rdmarsh2

swift/ql/lib/codeql/swift/controlflow/internal/ControlFlowGraphParameter.qll

@@ -1,3 +1,10 @@
+/**
+ * Provides the `CfgImpl` module that is used to construct the basic successor relation on control
+ * flow elements, and the `CfgInput` module that is used to construct `CgfImpl`.
+ * 
+ * See `ControlFlowGraphImpl.qll` for the auxiliary classes and predicates that map AST elements to
+ * control flow elements and sequence their children.
+ */
 import swift
 import codeql.controlflow.Cfg
 import codeql.util.Unit