add "player yxz is playing in game yxz" info to player context menü in the lobby

src/gui/qt/gamelobbydialog/gamelobbydialogimpl.h

@@ -142,6 +142,7 @@ private:
     QMenu *nickListContextMenu;
     QAction *nickListInviteAction;
     QAction *nickListIgnorePlayerAction;
+    QAction *nickListPlayerInGameInfo;
     int infoMsgToShowId;
     int currentInvitationGameId;
     bool inviteDialogIsCurrentlyShown;