Alternates media in multiple generated sitemap

### Link to the code that reproduces this issue https://codesandbox.io/p/devbox/practical-raman-plx3jf ### To Reproduce 1. Start the app (next dev) 2. Go to /pathname/sitemap/0.xml 3. See that we don't have the tag alternate for media ### Current vs. Expected behavior Expected xml ```xml <?xml version="1.0" encoding="UTF-8"?> <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:xhtml="http://www.w3.org/1999/xhtml"> <url> <loc>https://example.com/pathname/1</loc> <xhtml:link rel="alternate" media="only screen and (max-width: 640px)" href="https://m.example.com/pathname/1" /> </url> </urlset> ``` Actual xml ```xml <?xml version="1.0" encoding="UTF-8"?> <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:xhtml="http://www.w3.org/1999/xhtml"> <url> <loc>https://example.com/pathname/1</loc> </url> </urlset> ``` ### Provide environment information ```bash Operating System: Platform: linux Arch: x64 Version: #1 SMP PREEMPT_DYNAMIC Sun Aug 6 20:05:33 UTC 2023 Available memory (MB): 4102 Available CPU cores: 2 Binaries: Node: 20.9.0 npm: 9.8.1 Yarn: 1.22.19 pnpm: 8.10.2 Relevant Packages: next: 16.0.0-canary.15 // Latest available version is detected (16.0.0-canary.15). eslint-config-next: N/A react: 19.2.0 react-dom: 19.2.0 typescript: 5.3.3 Next.js Config: output: N/A ``` ### Which area(s) are affected? (Select all that apply) Webpack ### Which stage(s) are affected? (Select all that apply) next dev (local), next build (local), next start (local), Other (Deployed), Vercel (Deployed) ### Additional context _No response_