So I changed some other things to improve detection. I will update the post. But nice idea adding a hint! I personaly did that in a hint command also specifying other shortcuts and aliases about my zsh config.

Thanks for your reply! This made me think: could I bind enter to newline and alt-enter to accept, which then made me think if it was possible to have enter to accept and alt-enter to newline on first line only, after that in reverse. That made me think of the script I added to the post.

But serious, without this I would have never thought of doing what I did.

I updated my post to be clearer.