chore: add type annotations and resolve LSP warnings (#2555)

* chore: add type annotations to (almost) all functions

* stylua

* Add classes for symlink nodes

* Replace deprecated `@vararg`

* Move node classes to `node` module

* Fix `Symlink*` classes

* add vim and libuv runtime for luals, qualify libuv types

* add scripts/luals-check, not quite ready for CI

* additional nil checks for git/init.lua and git/runner.lua

* additional nil checks for nvim-tree.lua

* wrap vim.cmd-as-a-function calls inside functions

* vim.tbl_filter predicate returns booleans

* Revert "add scripts/luals-check, not quite ready for CI"

This reverts commit c70229cad9.

* Add `MinimalNode` class in `marks` module

* Fix various LSP warnings

* stylua

* Fix `Explorer` class, update related annotations and add necessary checks

* Add missing annotations to `live-filter`

* Add temporary aliases for `uv.*` types

* Resolve remaining LSP warnings

* Revert changes not related to internal types

* Minor adjustments

* Update doc comments style

* Minor adjustments (pt. 2)

---------

Co-authored-by: Alexander Courtis <alex@courtis.org>

lua/nvim-tree/explorer/sorters.lua

@@ -3,8 +3,8 @@ local M = {}
 local C = {}
 
 --- Predefined comparator, defaulting to name
---- @param sorter string as per options
---- @return function
+---@param sorter string as per options
+---@return function
 local function get_comparator(sorter)
   return C[sorter] or C.name
 end
@@ -24,8 +24,8 @@ local function tbl_slice(t, first, last)
 end
 
 ---Evaluate `sort.folders_first` and `sort.files_first`
----@param a table node
----@param b table node
+---@param a Node
+---@param b Node
 ---@return boolean|nil
 local function folders_or_files_first(a, b)
   if not (M.config.sort.folders_first or M.config.sort.files_first) then
@@ -41,6 +41,11 @@ local function folders_or_files_first(a, b)
   end
 end
 
+---@param t table
+---@param first number
+---@param mid number
+---@param last number
+---@param comparator fun(a: Node, b: Node): boolean
 local function merge(t, first, mid, last, comparator)
   local n1 = mid - first + 1
   local n2 = last - mid
@@ -74,6 +79,10 @@ local function merge(t, first, mid, last, comparator)
   end
 end
 
+---@param t table
+---@param first number
+---@param last number
+---@param comparator fun(a: Node, b: Node): boolean
 local function split_merge(t, first, last, comparator)
   if (last - first) < 1 then
     return
@@ -137,6 +146,10 @@ function M.sort(t)
   end
 end
 
+---@param a Node
+---@param b Node
+---@param ignorecase boolean|nil
+---@return boolean
 local function node_comparator_name_ignorecase_or_not(a, b, ignorecase)
   if not (a and b) then
     return true