wrapNeovimUnstable + nightly overlay: luajit buildEnv conflict

Wrapping neovim-nightly-overlay's package with nixpkgs wrapNeovimUnstable and nixpkgs vimPlugins fails with pkgs.buildEnv error: two given paths contain a conflicting subpath: .../luajit-.../bin/lua when the overlay does not follow your nixpkgs: the wrapper builds neovim-unwrapped.lua.withPackages from plugin luaDependencies (nvim-nio, luassert, say) built with a different luajit. Fixes: set neovim-nightly-overlay.inputs.nixpkgs.follows = "nixpkgs" (loses the nix-community cache, compiles nvim locally), or pass nightly // { inherit (pkgs.neovim-unwrapped) lua; } to the wrapper, which keeps the cached binary. Also: wrapRc = false keeps ~/.config/nvim/init.lua as entry; start-package plugins are require-able from init.lua because nvim's lua loader searches packpath start dirs.