docs: fix webpack.config.js example for ESM and CommonJS (#7735)

* docs: fix webpack.config.js example for ESM and CommonJS

* docs: fix markdown lint (MD031 blanks around fences)

* docs: restore ESM example and move __dirname logic below import

* docs: restore ESM example and move __dirname logic below import

* docs: restore original string literal formatting

* docs: quotes correction

Author: Kritank07

src/content/guides/getting-started.mdx

@@ -251,6 +251,10 @@ As of version 4, webpack doesn't require any configuration, but most projects wi
 
 ```javascript
 import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
 
 export default {
   entry: './src/index.js',