feat: Consistent and sensible layout_config (#922)

* feat: Consistent and sensible layout_config

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

* [WIP]: Thu 17 Jun 2021 03:36:44 PM EDT

* [WIP]: Thu 17 Jun 2021 03:38:11 PM EDT

* layout_default -> layout_defaults

* remove options from bug repot

* Conni2461 suggestions: part 1

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

* Conni2461 suggestions: part 2

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

* Linting

* Improve deprecation checks

- Move `layout_defaults` handling to `deprecated.lua`
- Check for "layout keys" outside of `layout_config` on `setup`

* fixup: Just add a few more words

Co-authored-by: Luke Kershaw <35707277+l-kershaw@users.noreply.github.com>
Co-authored-by: Github Actions <actions@github>

lua/tests/automated/pickers/find_files_spec.lua

@@ -35,8 +35,11 @@ describe('builtin.find_files', function()
         }, vim.tbl_extend("force", {
           disable_devicons = true,
           sorter = require('telescope.sorters').get_fzy_sorter(),
-          results_height = max_results,
           layout_strategy = 'center',
+          layout_config = {
+            height = max_results,
+            width = 0.9,
+          },
         }, vim.fn.json_decode([==[%s]==])))
       ]], vim.fn.json_encode(configuration)))
     end)
@@ -57,8 +60,11 @@ describe('builtin.find_files', function()
         }, vim.tbl_extend("force", {
           disable_devicons = true,
           sorter = require('telescope.sorters').get_fzy_sorter(),
-          results_height = 5,
           layout_strategy = 'center',
+          layout_config = {
+            height = max_results,
+            width = 0.9,
+          },
         }, vim.fn.json_decode([==[%s]==])))
       ]], expected, vim.fn.json_encode(configuration)))
     end)