Fix dependency problem

require 'nvim-web-devicons' fails if colors.setup done in plugin/. This
may be related to loading order.

lua/nvim-tree.lua

@@ -215,6 +215,7 @@ function M.xdg_open()
   end))
 end
 
+colors.setup()
 vim.defer_fn(M.on_enter, 1)
 
 return M

plugin/tree.vim

@@ -8,8 +8,6 @@ if get(g:, 'nvim_tree_disable_netrw', 1) == 1
     let g:loaded_netrwPlugin = 1
 endif
 
-lua require'nvim-tree'.reset_highlight()
-
 augroup NvimTree
   if get(g:, 'nvim_tree_hijack_netrw', 1) == 1 && get(g:, 'nvim_tree_disable_netrw', 1) == 0
     autocmd! FileExplorer *