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>

scripts/gendocs.lua

@@ -1,4 +1,5 @@
 -- Setup telescope with defaults
+if RELOAD then RELOAD('telescope') end
 require('telescope').setup()
 
 local docgen = require('docgen')
@@ -15,6 +16,7 @@ docs.test = function()
     "./lua/telescope/actions/state.lua",
     "./lua/telescope/actions/set.lua",
     "./lua/telescope/previewers/init.lua",
+    "./lua/telescope/config/resolve.lua",
     "./lua/telescope/themes.lua",
   }