Tooltip for "don't settle near my cities" promise

[LAnkou]

I had a game where I settled a city really near the AI. Of course, I was asked to stop settling near their land. I settled a second city between my core cities and the "too close" one... It was considered as a break of the promise.

That's why, on the settler layer, it should be nice to have a way to see where it would be considered a break of the "don't settle too close" promise...