Sitemap generation does not follow file location specification

### Link to the code that reproduces this issue https://github.com/dretsa/next-sitemap-spec ### To Reproduce 1. Generate multiple sitemaps as per documentation 2. Check paths generated and see they do not follow the specification Example - `/app/product/sitemap.ts` generates - from [docs example](https://nextjs.org/docs/app/api-reference/file-conventions/metadata/sitemap#generating-multiple-sitemaps): - `/product/sitemap/0.xml` - `/product/sitemap/1.xml` - `/product/sitemap/2.xml` - `/product/sitemap/3.xml` According to the specification, these sitemaps can only contain links starting with `/product/sitemap/.....`, as specified in the "Sitemap file location" section.  ### Current vs. Expected behavior I expect the generated sitemaps in a route `app/product/sitemap.ts` to allow me link `/product/...` pages. Currently they can only provide URLs starting with `/product/sitemap/...` ### Provide environment information ```bash Operating System: Platform: darwin Arch: arm64 Version: Darwin Kernel Version 24.3.0: Thu Jan 2 20:24:22 PST 2025; root:xnu-11215.81.4~3/RELEASE_ARM64_T6041 Available memory (MB): 49152 Available CPU cores: 14 Binaries: Node: 22.2.0 npm: 10.7.0 Yarn: 4.6.0 pnpm: N/A Relevant Packages: next: 15.1.7 eslint-config-next: 15.1.7 react: 19.0.0 react-dom: 19.0.0 typescript: 5.7.3 Next.js Config: output: standalone ``` ### Which area(s) are affected? (Select all that apply) Metadata, Route Handlers ### Which stage(s) are affected? (Select all that apply) next build (local), next start (local), next dev (local), Vercel (Deployed), Other (Deployed) ### Additional context _No response_