next.js

27d2fa28 - docs: remove Vercel mentions and improve deployment page (#78557)

docs: remove Vercel mentions and improve deployment page (#78557) This PR prunes references to Vercel in the documentation. Some of the mentions were egregious and unneeded. Others were documenting specific behavior for how Next.js runs on Vercel, which is better suited for the Vercel documentation. It also restructures our deployment documentation to remove any previous bias toward Vercel. Rather than separating self-hosting (Node.js server, Docker, static export) into its own section from managed platforms, it now lists them all together. Vercel is listed under "Adapters", alongside Netlify, Cloudflare, and AWS Amplify (in alphabetical order). These are the companies we're working with on the [Deployment Adapters API](https://github.com/vercel/next.js/discussions/77740), who currently maintain their own adapters and will eventually migrate to use this new API. We've [started working on](https://github.com/vercel/next.js/pull/78166) that API. For different features in the docs, like ISR or Middleware, this PR also adds a new feature matrix that shows the different deployment options and whether this feature is supported. For example, features that require using the server are not supported with static exports. Additionally, when there is configuration possible (like changing the caching behavior of ISR) we link back to our guide which explains these options in detail.  This PR also updates the Middleware section of the self-hosting guide to mention [Node.js runtime support](https://nextjs.org/blog/next-15-2#nodejs-middleware-experimental). I've also removed the "Managed Next.js (Vercel)" entry for the docs sidebar, as it is not necessary and Vercel should not have additional priority there over other providers.  Netlify has confirmed they're okay with the specific feature matrix link included in the adapters section, and I did my best to include the Cloudflare and Amplify versions based on their documentation. If any of the providers want to see changes to those links, please let me know and I'll open a PR.