Before the fix, the upper arm _ characters in the command's output would be parsed as Markdown italic formatting around the (ツ).
See MSC4291
Use the forget function to leave a room everywhere this is both for consistency and to reduce dependencies. This way no dependency on RoomManager is required to leave a room and since in all cases they have an object they can just call the function.
Move `NeoChatConnection` and `NeoChatRoom` to `LibNeoChat` along with any required dependencies.
