Revert "nvim: plugins: Drop sleuth now that neovim has editorconfig built-in"

This reverts commit 058c37882d.

It is still helpful to have this it seems as without this working on
projects which do not have editorconfig becomes a pain.

nvim/.config/nvim/lua/plugins.lua

@@ -47,6 +47,7 @@ local init = function ()
   -- Tim pope essentials
   use {
     'tpope/vim-repeat',
+    'tpope/vim-sleuth',
     'tpope/vim-dispatch'
   }
   -- Directory viewer