feat: add hide_root_folder (#728)

lua/nvim-tree/view.lua

@@ -9,6 +9,7 @@ end
 M.View = {
   bufnr = nil,
   tabpages = {},
+  hide_root_folder = false,
   winopts = {
     relativenumber = false,
     number = false,
@@ -144,6 +145,7 @@ function M.setup(opts)
   M.View.side = options.side
   M.View.width = options.width
   M.View.height = options.height
+  M.View.hide_root_folder = options.hide_root_folder
   M.View.auto_resize = opts.auto_resize
   if options.mappings.custom_only then
     M.View.mappings = options.mappings.list