`BufModifiedSet` autocmd no longer exists on nvim v0.13.0 (nightly)

### Description Neovim has dropped `BufModifiedSet` autocmd in https://github.com/neovim/neovim/pull/35610. nvim-tree fails to open its window for nightly users since this PR. Will need some shim and implementation using `OptionSet` with pattern `modified` instead for nightly versions, and drop current implementation at some point in the future. ### Neovim version ```text NVIM v0.13.0-dev-5180+g72bc6c5801-Homebrew Build type: Release LuaJIT 2.1.1774896198 ``` ### Operating system and version macOS ### Windows variant _No response_ ### nvim-tree version 24cfcc94372e526fd9e1c2803ede9e0f1715e33f ### Clean room replication ```lua for name, url in pairs({ tree = "https://github.com/nvim-tree/nvim-tree.lua.git", }) do local install_path = vim.fn.fnamemodify(string.format("/tmp/nvim_issue/%s", name), ":p") if vim.fn.isdirectory(install_path) == 0 then vim.fn.system({ "git", "clone", "--depth=1", url, install_path }) end vim.opt.runtimepath:append(install_path) end print("Minimal Config Ready!") require("nvim-tree").setup({ modified = { enable = true } }) ``` ### Steps to reproduce 1. `nvim --clean -u nvt-min.lua` 2. `:NvimTreeOpen` ### Expected behavior Open window and track modified files. ### Actual behavior ``` Lua :command callback: /tmp/nvim_issue/tree/lua/nvim-tree/explorer/init.lua:184: Invalid 'event': 'BufModifiedSet' stack traceback: [C]: in function 'nvim_create_autocmd' /tmp/nvim_issue/tree/lua/nvim-tree/explorer/init.lua:184: in function 'create_autocmds' /tmp/nvim_issue/tree/lua/nvim-tree/explorer/init.lua:73: in function 'new' /tmp/nvim_issue/tree/lua/nvim-tree/classic.lua:186: in function </tmp/nvim_issue/tree/lua/nvim-tree/classic.lua:184> /tmp/nvim_issue/tree/lua/nvim-tree/core.lua:30: in function 'init' /tmp/nvim_issue/tree/lua/nvim-tree/lib.lua:103: in function 'open' /tmp/nvim_issue/tree/lua/nvim-tree/actions/tree/open.lua:35: in function 'fn' /tmp/nvim_issue/tree/lua/nvim-tree/api/impl.lua:238: in function 'open' /tmp/nvim_issue/tree/lua/nvim-tree/commands.lua:13: in function </tmp/nvim_issue/tree/lua/nvim-tree/commands.lua:12> ```