refactor(#2886): multi instance: node group functions refactoring (#2959)

* move last_group_node to DirectoryNode

* move add BaseNode:as and more doc

* revert parameter name changes

* revert parameter name changes

* add Class

* move group methods into DN

* tidy group methods

* tidy group methods

* tidy group methods

* tidy group methods

* parent is DirectoryNode

* tidy expand all

* BaseNode -> Node

* move watcher to DirectoryNode

* last_group_node is DirectoryNode only

* simplify create-file

* simplify parent

* simplify collapse-all

* simplify live-filter

* style

lua/nvim-tree/node/file.lua

@@ -1,15 +1,15 @@
 local git = require("nvim-tree.git")
 local utils = require("nvim-tree.utils")
 
-local BaseNode = require("nvim-tree.node")
+local Node = require("nvim-tree.node")
 
----@class (exact) FileNode: BaseNode
+---@class (exact) FileNode: Node
 ---@field extension string
-local FileNode = BaseNode:new()
+local FileNode = Node:new()
 
 ---Static factory method
 ---@param explorer Explorer
----@param parent Node
+---@param parent DirectoryNode
 ---@param absolute_path string
 ---@param name string
 ---@param fs_stat uv.fs_stat.result?
@@ -27,7 +27,6 @@ function FileNode:create(explorer, parent, absolute_path, name, fs_stat)
     is_dot = false,
     name = name,
     parent = parent,
-    watcher = nil,
     diag_status = nil,
 
     extension = string.match(name, ".?[^.]+%.(.*)") or "",
@@ -56,7 +55,7 @@ end
 ---Create a sanitized partial copy of a node
 ---@return FileNode cloned
 function FileNode:clone()
-  local clone = BaseNode.clone(self) --[[@as FileNode]]
+  local clone = Node.clone(self) --[[@as FileNode]]
 
   clone.extension = self.extension