note prohibited countries for Binance.com API

[X1011]

I was not able to use the Binance.com API from the US:

ccxt.base.errors.ExchangeNotAvailable: binance GET https://api.binance.com/api/v3/exchangeInfo 451 {
"code": 0,
"msg": "Service unavailable from a restricted location according to 'b. Eligibility' in https://www.binance.com/en/terms. Please contact customer service if you believe you received this message in error."

[macanudo527]

@X1011 Thanks for this. I thought I coded a better warning than that, but this is good documentation until I can get to it.

[macanudo527]

LGTM!