[clang] modified AST for SEI redemption project (PR #111705)

[Aaron Ballman via cfe-commits]

================
@@ -410,8 +447,17 @@ class ASTNodeTraverser
     Visit(T->getSizeExpr());
   }
   void VisitVectorType(const VectorType *T) { Visit(T->getElementType()); }
-  void VisitFunctionType(const FunctionType *T) { Visit(T->getReturnType()); }
+  void VisitFunctionType(const FunctionType *T) {
+    // SEI: add functionDetails, incl. return type
+    getNodeDelegate().AddChild("functionDetails", [this, T] {
+      getNodeDelegate().VisitFunctionType(T);
+      getNodeDelegate().VisitReturnType(T->getReturnType());
+    });
+  }
+
   void VisitFunctionProtoType(const FunctionProtoType *T) {
+
+    // SEI: visit the function type. this will force the return type info too.
----------------
AaronBallman wrote:

```suggestion
    // Visiting the function type will force the return type info too.
```

https://github.com/llvm/llvm-project/pull/111705