Add missing channel definitions

[hecksadecimal]

New channel types cause issues with logging in when the bot or user account exists in a server containing either of the following:

• Guild Stage Voice
• Guild Forum

I've added those and these others, which I have not encountered on any of my own accounts yet but expect to cause a similar error sooner or later:

• Guild News Thread
• Guild Public Thread
• Guild Private Thread
• Guild Directory

[SpaceManiac]

Do you have any reference covering the removal of large_threshold?