Add part/leave command

src/timeline/InputBar.cpp

@@ -482,6 +482,8 @@ InputBar::command(QString command, QString args)
                           eventId, args.trimmed());
         } else if (command == "join") {
                 ChatPage::instance()->joinRoom(args);
+        } else if (command == "part" || command == "leave") {
+                MainWindow::instance()->openLeaveRoomDialog(room->roomId());
         } else if (command == "invite") {
                 ChatPage::instance()->inviteUser(args.section(' ', 0, 0), args.section(' ', 1, -1));
         } else if (command == "kick") {