Add new FAQ: "My tx was in a 2 tx block. Is my privacy still protected by Monero?"

[CryptoGrampy]

Creating this issue as result of multiple people including Rucknium and BTC maxi's like Diverter discussing this question in the Monero channel on 11/21. It would be helpful to explain this issue as though someone is unfamiliar with Monero tech, perhaps including an analogy/statistics/links to more info as well.

[Rucknium]

I am willing to review such a FAQ for correctness. I don't want to write it though. You don't want the FAQ to start out with, "Imagine that you are a probability density function that wishes to protect Monero user privacy...". @j-berman could maybe help review, as well.