Return a error on a invalid token

[netspl0it]

Is your feature request related to a problem? Please describe.
The bot will not return an error when a token is invalid which can lead to a panic.

Describe the solution you'd like
On *.OpenGateway return an error if the bot cannot connect due to a invalid token/un-connectable error, that the user can handle in their nessesary way.

Describe alternatives you've considered
For now I am using latency to discover if the bot's connection was successful before proceeding to continue to actions to prevent said panic.

Additional context
In my case running multiple bots caused the bot to restart via process manager due to a bad overlook on my part with no knowledge of the error occurring that I thought was handled due to the OpenGateway returning a error, I did not understand that a bad token would not give a error for me to handle which in turn caused the main process bot's token to be reset overnight.