Neovim setup

Can it be this easy to make nvim stuff just work? Do I really just need
to pull the files in with Home Manager? It seems so, so long as nvim
knows about gcc :)

There is also a related side of tmux here because it all ties together.

modules/home-manager/files/nvim/lua/plugins/vim-tmux-navigator.lua

@@ -0,0 +1,3 @@
+return {
+  "christoomey/vim-tmux-navigator"
+}