refactor(options): update extui import path per neovim/neovim@bf68ba4

neovim/neovim@bf68ba4

Author: kang8

lua/config/options.lua

@@ -28,7 +28,7 @@ vim.diagnostic.config({
 })
 
 if vim.fn.has('nvim-0.12') == 1 and not vim.g.vscode then
-  require('vim._extui').enable({})
+  require('vim._core.ui2').enable({})
 end
 
 vim.opt.maxsearchcount = 9999