This setting defines what channels can the .suggest command be used in.
Set up commands channels using .config commands add/remove/list [channel], setting none as the channel will reset the current configuration and thus will allow the command to be used in any channel
commandchannels, command, commandchannel and commands
Any channel name, id or #mention
?> Forum Channels are not currently supported and may not be configured as a command channel (commands posted in threads or inside forum threads will be ignored).