refactor: add missing file paths (for browser compatibility)

Author: brettz9

index.js

@@ -1,5 +1,5 @@
 import * as acorn from "acorn";
-import XHTMLEntities from './xhtml';
+import XHTMLEntities from './xhtml.js';
 
 const hexNumber = /^[\da-fA-F]+$/;
 const decimalNumber = /^\d+$/;

test/tests-misc.js

@@ -1,7 +1,7 @@
 import assert from "assert";
 import * as acorn from "acorn";
 import jsx from "../index.js";
-import { testAssert } from "./driver";
+import { testAssert } from "./driver.js";
 
 testAssert("// the enhanced Parser instance should have a static property 'acornJsx'.", function() {
   const JsxParser = acorn.Parser.extend(jsx());