Doc about replacement cycling attacks

[hieblmi]

Hi @t-bast,

I am sure that your pages about lightning are a great learning resource for many lightning devs and enthusiats.
It would be great to see a document in this repo about mempool replacement cycling attacks that everyone got aware of now through this post, maybe in a similar fashion as you describe pinning attacks.

All the best.

[t-bast]

Good idea! A detailed post about mempool subtleties and their impact on L2 protocols would be generally useful, I'll do that when I find some time.