feat: add ivy-style layout strategy (#771)

* feat: add new layout strategy

* [docgen] Update doc/telescope.txt
skip-checks: true

Co-authored-by: Github Actions <actions@github>

lua/telescope/pickers/window.lua

@@ -1,10 +1,10 @@
-local p_layouts = require('telescope.pickers.layout_strategies')
+local resolve = require("telescope.config.resolve")
 
 local p_window = {}
 
 function p_window.get_window_options(picker, max_columns, max_lines)
   local layout_strategy = picker.layout_strategy
-  local getter = p_layouts[layout_strategy]
+  local getter = require('telescope.pickers.layout_strategies')[layout_strategy]
 
   if not getter then
     error("Not a valid layout strategy: " .. layout_strategy)
@@ -13,5 +13,38 @@ function p_window.get_window_options(picker, max_columns, max_lines)
   return getter(picker, max_columns, max_lines)
 end
 
+function p_window.get_initial_window_options(picker)
+  local popup_border = resolve.win_option(picker.window.border)
+  local popup_borderchars = resolve.win_option(picker.window.borderchars)
+
+  local preview = {
+    title = picker.preview_title,
+    border = popup_border.preview,
+    borderchars = popup_borderchars.preview,
+    enter = false,
+    highlight = false
+  }
+
+  local results = {
+    title = picker.results_title,
+    border = popup_border.results,
+    borderchars = popup_borderchars.results,
+    enter = false,
+  }
+
+  local prompt = {
+    title = picker.prompt_title,
+    border = popup_border.prompt,
+    borderchars = popup_borderchars.prompt,
+    enter = true
+  }
+
+  return {
+    preview = preview,
+    results = results,
+    prompt = prompt,
+  }
+end
+
 
 return p_window