STD has been replaced by STN

[tagliala]

Hi,

I was double checking money's currency table against another table to look for differences and I've noticed that STN is missing

Quoting from: https://en.wikipedia.org/wiki/S%C3%A3o_Tom%C3%A9_and_Pr%C3%ADncipe_dobra

The first dobra (STD) was introduced in 1977, replacing the escudo at par. Due to past inflation, on 1 January 2018 the dobra was redenominated at a rate of 1000 to 1, and given the new ISO 4217 currency code STN.[1]
[...]
With the redenomination of the dobra in 2018, coins were introduced in denominations of 10, 20, and 50 cêntimos and one and two dobras.

I'm not confident in submitting a PR because I don't know how smallest_denomination and maybe other fields should change