Review suggestions.

libsolidity/ast/ASTAnnotations.h

@@ -130,7 +130,11 @@ struct TypeDeclarationAnnotation: DeclarationAnnotation
 
 struct StructDeclarationAnnotation: TypeDeclarationAnnotation
 {
-	/// Whether the struct is recursive. Will be filled in by the DeclarationTypeChecker.
+	/// Whether the struct is recursive, i.e. if the struct (recursively) contains a member that involves a struct of the same
+	/// type, either in a dynamic array, as member of another struct or inside a mapping.
+	/// Only cases in which the recursive occurrence is within a dynamic array or a mapping are valid, while direct
+	/// recursion immediately raises an error.
+	/// Will be filled in by the DeclarationTypeChecker.
 	std::optional<bool> recursive;
 };