/** Called when a user parts a channel.
* The details of the leaving user are available to you in the parameter User *user,
* and the details of the channel they have left is available in the variable Channel *channel
* @param memb The channel membership being destroyed
* @param partmessage The part message, or an empty string (may be modified)
/** Called when a user parts a channel.
* The details of the leaving user are available to you in the parameter User *user,
* and the details of the channel they have left is available in the variable Channel *channel
* @param memb The channel membership being destroyed
* @param partmessage The part message, or an empty string (may be modified)