Modernize deprecated Neovim APIs

vim.loop -> vim.uv and vim.highlight.range -> vim.hl.range. Also drop the
completeopt comment referring to nvim-cmp, which blink.cmp replaced.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

lua/config/lazy.lua

@@ -1,5 +1,5 @@
 local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
-if not vim.loop.fs_stat(lazypath) then
+if not vim.uv.fs_stat(lazypath) then
   -- bootstrap lazy.nvim
   -- stylua: ignore
   vim.fn.system({ "git", "clone", "--filter=blob:none", "https://github.com/folke/lazy.nvim.git", "--branch=stable", lazypath })