fix(types): ensure all fields for LazyPluginSpec are optional (#1843)

> After updating lua_ls to
[v3.13.3](https://github.com/LuaLS/lua-language-server/releases/tag/3.13.3)
noticed my plugin scripts using `@type LazyPluginSpec` now have
`missing-fields` warnings.
It seems they have changed how `missing-fields` diagnostics work with
inherited types:
LuaLS/lua-language-server@7b2d585.

Duplicate offending fields as optional in type `LazyPluginSpec`

Closes: #1842

Author: daephx

lua/lazy/types.lua

@@ -75,6 +75,8 @@
 ---@field module? false
 
 ---@class LazyPluginSpec: LazyPluginBase,LazyPluginSpecHandlers,LazyPluginHooks,LazyPluginRef
+---@field name? string display name and name used for plugin config files
+---@field dir? string
 ---@field dependencies? string|string[]|LazyPluginSpec[]
 ---@field specs? string|string[]|LazyPluginSpec[]