Function set_chat_description 

pub async fn set_chat_description(
    context: &Context,
    chat_id: ChatId,
    new_description: &str,
) -> Result<()>

Set group or broadcast channel description.

If the group is already promoted (any message was sent to the group), or if this is a brodacast channel, all members are informed by a special status message that is sent automatically by this function.

Sends out #DC_EVENT_CHAT_MODIFIED and #DC_EVENT_MSGS_CHANGED if a status message was sent.

See also get_chat_description