Update docs/content/docs/2.storage/3.blob.md

Author: atinux

docs/content/docs/2.storage/3.blob.md

@@ -277,7 +277,7 @@ export default eventHandler(async (event) => {
 
 A simple example of multipart upload in client with above routes:
 
-```ts
+```ts [utils/multipart-upload.ts]
 async function uploadLargeFile(file: File) {
   const chunkSize = 10 * 1024 * 1024 // 10MB