Code diff highlighting not working

This is what's rendering, at least on the Start migration page. I couldn't find another issue for this but if there is one, apologies for the duplicate.

- export default async function Page({ // [!code --]
-   params, // [!code --]
- }: { // [!code --]
-   params: Promise<{ slug: string }> // [!code --]
- }) { // [!code --]
+ export const Route = createFileRoute('/app/posts/$slug')({ // [!code ++]
+   component: Page, // [!code ++]
+ }) // [!code ++]

+ function Page() { // [!code ++]
-   const { slug } = await params // [!code --]
+   const { slug } = Route.useParams() // [!code ++]
  return <div>My Post: {slug}</div>
}

Start at the Start migration page and inspect how the shown code block is rendered, comparing the expected diff markers with the displayed output. Trace the page's code-highlighting path and verify the fix by confirming that added and removed lines render with the intended highlighting.