add classic, migrating nodes classes

lua/nvim-tree/node/root.lua

@@ -1,20 +1,14 @@
 local DirectoryNode = require("nvim-tree.node.directory")
 
 ---@class (exact) RootNode: DirectoryNode
-local RootNode = DirectoryNode:new()
+local RootNode = DirectoryNode:extend()
 
----Static factory method
 ---@param explorer Explorer
 ---@param absolute_path string
 ---@param name string
 ---@param fs_stat uv.fs_stat.result|nil
----@return RootNode
-function RootNode:create(explorer, absolute_path, name, fs_stat)
-  local o = DirectoryNode:create(explorer, nil, absolute_path, name, fs_stat)
-
-  o = self:new(o)
-
-  return o
+function RootNode:new(explorer, absolute_path, name, fs_stat)
+  RootNode.super.new(self, explorer, nil, absolute_path, name, fs_stat)
 end
 
 ---Root is never a dotfile