This is a really simple patch but does, I think, have the potential to be useful. Basically, any arguments given to the server quit command will be sent to all clients in SV_FinalMessage, which should show up in their disconnect error message.
So a server owner can do something like "quit Server restarting for upgrade" and all the clients will know to reconnect in a second.
Or "quit You're two weeks behind on your rental bill, get it together" as the case may be.
Created attachment 1781 [details] quit arguments handling I tested this with Tremulous briefly. Client quits with or without arguments seem unaffected.