api/window_set_cursor: make sure cursor line is visible.

Previously, the cursor could be left outside the visible range if window
is not the current window

src/nvim/api/window.c

@@ -9,6 +9,7 @@
 #include "nvim/cursor.h"
 #include "nvim/window.h"
 #include "nvim/screen.h"
+#include "nvim/move.h"
 #include "nvim/misc2.h"
 
 
@@ -86,6 +87,10 @@ void window_set_cursor(Window window, ArrayOf(Integer, 2) pos, Error *err)
   win->w_cursor.coladd = 0;
   // When column is out of range silently correct it.
   check_cursor_col_win(win);
+
+  // make sure cursor is in visible range even if win != curwin
+  update_topline_win(win);
+
   update_screen(VALID);
 }