docs: add JS syntax highlighting for Vercel images config example (#1…

…2361)

documentation/docs/25-build-and-deploy/90-adapter-vercel.md

@@ -68,7 +68,8 @@ If your functions need to access data in a specific region, it's recommended tha
 
 You may set the `images` config to control how Vercel builds your images. See the [image configuration reference](https://vercel.com/docs/build-output-api/v3/configuration#images) for full details. As an example, you may set:
 
-```
+```js
+// @errors: 2300 2842 7031 1181 1005 1136 1128
 /// file: svelte.config.js
 import adapter from '@sveltejs/adapter-vercel';