Return the screen position of window {nr} as a list with two numbers: [row, col]. The first window always has position [1, 1], unless there is a tabline, then it is [2, 1]. {nr} can be the window number or the |window-ID|. Use zero for the current window. Return [0, 0] if the window cannot be found in the current tabpage. Can also be used as a |method|: GetWinid()->win_screenpos()