docs(ppr): update note about ppr (#71697)

## Why?

Let's clarify this is only available in canary. We need to remove it
from the stable docs later.

docs/02-app/01-building-your-application/03-rendering/04-partial-prerendering.mdx

@@ -3,12 +3,12 @@ title: Partial Prerendering
 description: Learn how to combine the benefits of static and dynamic rendering with Partial Prerendering.
 ---
 
+> **Note:** Partial Prerendering is an **experimental** feature only available on canary and is subject to change. It is not ready for production use.
+
 Partial Prerendering (PPR) enables you to combine static and dynamic components together in the same route.
 
 During the build, Next.js prerenders as much of the route as possible. If [dynamic](/docs/app/building-your-application/rendering/server-components#dynamic-rendering) code is detected, like reading from the incoming request, you can wrap the relevant component with a [React Suspense](https://react.dev/reference/react/Suspense) boundary. The Suspense boundary fallback will then be included in the prerendered HTML.
 
-> **Note:** Partial Prerendering is an **experimental** feature and subject to change. It is not ready for production use.
-
 <Image
   alt="Partially Prerendered Product Page showing static nav and product information, and dynamic cart and recommended products"
   srcLight="/learn/light/thinking-in-ppr.png"