Enable math in markdown preview

Fixes #124783

extensions/markdown-math/extension-browser.webpack.config.js

@@ -0,0 +1,17 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+//@ts-check
+
+'use strict';
+
+const withBrowserDefaults = require('../shared.webpack.config').browser;
+
+module.exports = withBrowserDefaults({
+	context: __dirname,
+	entry: {
+		extension: './src/extension.ts'
+	}
+});