Added comments to middleware-matcher example (#40273)

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`

## Documentation / Examples

- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)


Co-authored-by: Balázs Orbán <18369201+balazsorban44@users.noreply.github.com>

examples/middleware-matcher/middleware.js

@@ -11,5 +11,8 @@ export default function middleware(req) {
 }
 
 export const config = {
-  matcher: ['/public/disclaimer', '/((?!public|static).*)'],
+  matcher: [
+    '/disclaimer', // match a single, specific page
+    '/((?!public|static).*)', // match all paths not starting with 'public' or 'static'
+  ],
 }