docs(start/v2): mention removed polyfills

docs/start/v2.md

@@ -945,6 +945,89 @@ import { installGlobals } from "@remix-run/node";
 installGlobals();
 ```
 
+### Removal of exported polyfills
+
+Remix v2 also no longer exports these polyfilled implementations from `@remix-run/node`, and instead you should just use the instances in the global namespace. One place this is likely to surface and require a change is your `entry.server.tsx` file, where you'll also need to convert the Node `PassThrough` into a web `ReadableStream` via `createReadableStreamFromReadable`:
+
+```diff
+  import { PassThrough } from "node:stream";
+  import type { AppLoadContext, EntryContext } from "@remix-run/node";
+- import { Response } from "@remix-run/node";
++ import { createReadableStreamFromReadable } from "@remix-run/node";
+  import { RemixServer } from "@remix-run/react";
+  import isbot from "isbot";
+  import { renderToPipeableStream } from "react-dom/server";
+
+  const ABORT_DELAY = 5_000;
+
+  export default function handleRequest({ /* ... */ }) { ... }
+
+  function handleBotRequest(...) {
+    return new Promise((resolve, reject) => {
+      let shellRendered = false;
+      const { pipe, abort } = renderToPipeableStream(
+        <RemixServer ... />,
+        {
+          onAllReady() {
+            shellRendered = true;
+            const body = new PassThrough();
++           const stream = createReadableStreamFromReadable(body);
+
+            responseHeaders.set("Content-Type", "text/html");
+
+            resolve(
+-             new Response(body, {
++             new Response(stream, {
+                headers: responseHeaders,
+                status: responseStatusCode,
+              })
+            );
+
+            pipe(body);
+          },
+          ...
+          onShellError(error: unknown) { ... }
+          onError(error: unknown) { ... }
+        }
+      );
+
+      setTimeout(abort, ABORT_DELAY);
+    });
+  }
+
+  function handleBrowserRequest(...) {
+    return new Promise((resolve, reject) => {
+      let shellRendered = false;
+      const { pipe, abort } = renderToPipeableStream(
+        <RemixServer ... />,
+        {
+          onShellReady() {
+            shellRendered = true;
+            const body = new PassThrough();
++           const stream = createReadableStreamFromReadable(body);
+
+            responseHeaders.set("Content-Type", "text/html");
+
+            resolve(
+-              new Response(body, {
++              new Response(stream, {
+                headers: responseHeaders,
+                status: responseStatusCode,
+              })
+            );
+
+            pipe(body);
+          },
+          onShellError(error: unknown) { ... },
+          onError(error: unknown) { ... },
+        }
+      );
+
+      setTimeout(abort, ABORT_DELAY);
+    });
+  }
+```
+
 ## `source-map-support`
 
 Source map support is now a responsibility of the app server. If you are using `remix-serve`, nothing is required. If you are using your own app server, you will need to install [`source-map-support`][source-map-support] yourself.