improved documentation of new buffering changelog

Author: shairez

.changeset/fair-cars-fry.md

@@ -19,13 +19,13 @@ FEAT: Major improvements to prefetching with automatic bundle preloading
 - **Keep** your service worker code as is (either `<ServiceWorkerRegister/>` or `<PrefetchServiceWorker/>`).
 - **Configure** your server to provide long caching headers.
 
-Service Worker:
+**Service Worker:**
 
 This new implementation will use it to uninstall the current service worker to reduce the unnecessary duplication.
 
 The builtin service workers components are deprecated but still exist for backwards compatibility.
 
-Caching Headers:
+ ⚠️ **IMPORTANT: Caching Headers:**
 
 The files under build/ and assets/ are named with their content hash and may therefore be cached indefinitely. Typically you should serve `build/*` and `assets/*` with `Cache-Control: public, max-age=31536000, immutable`.
 
@@ -53,6 +53,8 @@ export default function (opts: RenderToStreamOptions) {
 }
 ```
 
+#### Optional for legacy apps: 
+
 For legacy apps that still need service worker functionality, you can add it back using:
 
 ```bash