add autocmd for wrapping text in markdown

.config/nvim/lua/core/autocmds.lua

@@ -0,0 +1,6 @@
+vim.api.nvim_create_autocmd("FileType", {
+   pattern = "markdown",
+   callback = function()
+      vim.opt_local.textwidth = 80
+   end,
+})

.config/nvim/lua/core/init.lua

@@ -1,2 +1,3 @@
 require "core.options"
 require "core.keymap"
+require "core.autocmds"