C++: Add change note

Author: jketema

cpp/ql/lib/change-notes/2025-04-23-typeof.md

@@ -0,0 +1,5 @@
+---
+category: feature
+---
+* New classes `TypeofType`, `TypeofExprType`, and `TypeofTypeType` were introduced, which represent the C23 `typeof` and `typeof_unqual` operators. The `TypeofExprType` class represents the variant taking an expression as its argument. The `TypeofTypeType` class represents the variant taking a type as its argument.
+* A new class `IntrinsicTransformedType` was introduced, which represents the type transforming intrinsics supported by clang, gcc, and MSVC.