add bindings and fix documentation

bindings/node/binding_test.js

@@ -0,0 +1,11 @@
+import assert from "node:assert";
+import { test } from "node:test";
+import Parser from "tree-sitter";
+
+test("can load grammar", () => {
+  const parser = new Parser();
+  assert.doesNotReject(async () => {
+    const { default: language } = await import("./index.js");
+    parser.setLanguage(language);
+  });
+});