Allow opening the quickmenu player name selection by trying to send an empty message

With this new feature, the quickmenu player name selection can be opened easily and directly from the chat by trying to send the initial empty message (empty messages don't get sent anyway) with 2 keystrokes: T-Enter.

Currently the same result can be achieved by manually opening the quickmenu, entering Chat submenu and clicking on "Send public message to". Using only the keyboard is 3 keystrokes: F8-1-1.