react-dom/server: clarify when `renderToPipeableStream` is appropriate

[isker]

At https://reactjs.org/docs/react-dom-server.html#rendertopipeablestream we see this note:

This is a Node.js specific API and modern server environments should use renderToReadableStream instead.

I initially read this as saying "use renderToReadableStream in any environment where web streams are available." This includes modern versions of Node: https://nodejs.org/api/webstreams.html.

But going to the main React 18 release notes page https://reactjs.org/blog/2022/03/29/react-v18.html#react-dom-server, we see that there is a different distinction being made.

renderToPipeableStream: for streaming in Node environments.
renderToReadableStream: for modern edge runtime environments, such as Deno and Cloudflare workers.

(Aside: is Deno really an "edge runtime environment"? 🤔 )

Combined with @sebmarkbage's outlining of the downsides of web streams here reactwg/react-18#91, it seems clear that renderToPipeableStream should always be preferred in Node environments. It'd be nice if the docs clearly spelled this out.