Maybe, if it’s created after the text is generated. Keep in mind there really is no white space to an LLM. There’s a lot of holes here. If it isn’t embedded within the text itself, it is trivially easy to strip such markings. If it is, it at least requires a human to paraphrase.
On the other hand, if that’s all it is, it would be easily detectable to disallow AI from editing human-written code while allowing it to revise its own output.