minor cleanup

shell.nix

@@ -0,0 +1,16 @@
+{ nixpkgs ? import <nixpkgs> {  } }:
+ 
+let
+  pkgs = [
+    nixpkgs.nodejs
+  ];
+ 
+in
+  nixpkgs.stdenv.mkDerivation {
+    name = "env";
+    buildInputs = pkgs;
+    shellHook = ''
+        PATH=./node_modules/.bin:$PATH
+        command -v tree-sitter >/dev/null 2>&1 || npm install tree-sitter-cli
+    '';
+  }