[errors] Improve NotGeneric error message

src/builtins/builtins-function.cc

Index: src/builtins/builtins-function.cc
diff --git a/src/builtins/builtins-function.cc b/src/builtins/builtins-function.cc
index d93c2ee80bf1043bb926dbd36d1dcda923681559..7db1899b64e96f4e8f9be975a92aeb47907bbb47 100644
--- a/src/builtins/builtins-function.cc
+++ b/src/builtins/builtins-function.cc
@@ -312,7 +312,8 @@ BUILTIN(FunctionPrototypeToString) {
   THROW_NEW_ERROR_RETURN_FAILURE(
       isolate, NewTypeError(MessageTemplate::kNotGeneric,
                             isolate->factory()->NewStringFromAsciiChecked(
-                                "Function.prototype.toString")));
+                                "Function.prototype.toString"),
+                            isolate->factory()->Function_string()));
 }
 
 }  // namespace internal