feat(nix): nix and back again

I tried Nix, but it had too many downsides so I removed it.

1. Didn't like that all files are immutable and simple config changes
need a complete rebuild.
2. Setting up a new Mac didn't work as smoothly as promised. Not worth
the effort.
3. It sucked a lot to always have to type in the password twice on each
darwin-rebuild
4. It solves problems I never had.

.config/nvim/lua/plugins/abolish.lua

@@ -0,0 +1,9 @@
+-- Automatically fix spelling mistakes
+-- https://github.com/tpope/vim-abolish
+return {
+  "tpope/vim-abolish",
+  config = function()
+    vim.api.nvim_command("Abolish teh the")
+    vim.api.nvim_command("Abolish {despa,sepe}rat{e,es,ed,ing,ely,ion,ions,or}  {despe,sepa}rat{}")
+  end,
+}