[feat] Link to Telegram limits in the ReadMe / docs

[TangentFoxy]

Is your feature request related to a problem? Please describe.
The ReadMe warns about limits multiple times, but doesn't give any indication of what these limits are or where to find out what they are.

Describe the solution you'd like
After searching through closed issues, I found https://limits.tginfo.me/
Is this even correct? If not, could the correct limits be linked to?

[phanirithvij]

I've read somewhere that 1 million is the files limit per channel. Can't verify myself.