Readme example comment mistake for Websocket part

[InfectedIsm]

Hi,
first of all thank you for your code, it is a precious help.

It seems to me that :

• "BTC Symbol snapshots" should be "BTC Market snapshot"
• "KCS-BTC Market snapshots" should be "KCS-BTC Symbol snapshots"

as per Kucoin documentation here : https://docs.kucoin.com/#symbol-snapshot

 # Note: try these one at a time, if all are on you will see a lot of output

    # ETH-USDT Market Ticker
    await ksm.subscribe('/market/ticker:ETH-USDT')
    **# BTC Symbol Snapshots**
    await ksm.subscribe('/market/snapshot:BTC')
    **# KCS-BTC Market Snapshots**
    await ksm.subscribe('/market/snapshot:KCS-BTC')
    # All tickers