Fix resize/preview toggles of the cursor layout (#2718)

The cursor layout uses winline() and wincol() to calculate the cursor
position. Both these functions operate on the currently active window.
The first time the calculations are performed, that happens to be the
window active before showing the Telescope window. However, if the
editor is then resized or the preview window is toggled, the active
window changes. The result is that recalculating the position is then
done using the wrong window, resulting in the Telescope window moving
around in an erratic manner.

To fix this, we have to scope the winline() and wincol() calls to the
original window ID.

lua/telescope/pickers/layout_strategies.lua

@@ -565,6 +565,7 @@ layout_strategies.cursor = make_documented_layout(
     local preview = initial_options.preview
     local results = initial_options.results
     local prompt = initial_options.prompt
+    local winid = self.original_win_id
 
     local height_opt = layout_config.height
     local height = resolve.resolve_height(height_opt)(self, max_columns, max_lines)
@@ -599,16 +600,16 @@ layout_strategies.cursor = make_documented_layout(
       results.width = prompt.width
     end
 
-    local position = vim.api.nvim_win_get_position(0)
+    local position = vim.api.nvim_win_get_position(winid)
     local winbar = (function()
       if vim.fn.exists "&winbar" == 1 then
-        return vim.o.winbar == "" and 0 or 1
+        return vim.wo[winid].winbar == "" and 0 or 1
       end
       return 0
     end)()
     local top_left = {
-      line = vim.fn.winline() + position[1] + bs + winbar,
-      col = vim.fn.wincol() + position[2],
+      line = vim.api.nvim_win_call(winid, vim.fn.winline) + position[1] + bs + winbar,
+      col = vim.api.nvim_win_call(winid, vim.fn.wincol) + position[2],
     }
     local bot_right = {
       line = top_left.line + height - 1,