vim-patch:8.0.1364: there is no easy way to get the window position

Problem:    There is no easy way to get the window position.
Solution:   Add win_screenpos().
vim/vim@22044dc

runtime/doc/eval.txt

@@ -2352,6 +2352,7 @@ win_getid([{win} [, {tab}]])	Number	get |window-ID| for {win} in {tab}
 win_gotoid({expr})		Number	go to |window-ID| {expr}
 win_id2tabwin({expr})		List	get tab and window nr from |window-ID|
 win_id2win({expr})		Number	get window nr from |window-ID|
+win_screenpos({nr})		List	get screen position of window {nr}
 winbufnr({nr})			Number	buffer number of window {nr}
 wincol()			Number	window column of the cursor
 winheight({nr})			Number	height of window {nr}
@@ -8181,6 +8182,14 @@ win_id2win({expr})					*win_id2win()*
 		Return the window number of window with ID {expr}.
 		Return 0 if the window cannot be found in the current tabpage.
 
+win_screenpos({nr})					*win_screenpos()*
+		Return the screen position of window {nr} as a list with two
+		numbers: [row, col].  The first window always has position
+		[1, 1].
+		{nr} can be the window number or the |window-ID|.
+		Return [0, 0] if the window cannot be found in the current
+		tabpage.
+
 							*winbufnr()*
 winbufnr({nr})	The result is a Number, which is the number of the buffer
 		associated with window {nr}.  {nr} can be the window number or

src/nvim/eval.c

@@ -10310,6 +10310,15 @@ static void f_getwininfo(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 }
 
+// "win_screenpos()" function
+static void f_win_screenpos(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  tv_list_alloc_ret(rettv, 2);
+  const win_T *const wp = find_win_by_nr(&argvars[0], NULL);
+  tv_list_append_number(rettv->vval.v_list, wp == NULL ? 0 : wp->w_winrow + 1);
+  tv_list_append_number(rettv->vval.v_list, wp == NULL ? 0 : wp->w_wincol + 1);
+}
+
 /*
  * "getwinposx()" function
  */

src/nvim/eval.lua

@@ -338,6 +338,7 @@ return {
     win_gotoid={args=1},
     win_id2tabwin={args=1},
     win_id2win={args=1},
+    win_screenpos={args=1},
     winbufnr={args=1},
     wincol={},
     winheight={args=1},

src/nvim/testdir/test_window_cmd.vim

@@ -374,6 +374,19 @@ func Test_equalalways_on_close()
   set equalalways&
 endfunc
 
+func Test_win_screenpos()
+  call assert_equal(1, winnr('$'))
+  split
+  vsplit
+  10wincmd _
+  30wincmd |
+  call assert_equal([1, 1], win_screenpos(1))
+  call assert_equal([1, 32], win_screenpos(2))
+  call assert_equal([12, 1], win_screenpos(3))
+  call assert_equal([0, 0], win_screenpos(4))
+  only
+endfunc
+
 func Test_window_jump_tag()
   help
   /iccf