[Bug]: Example given in "Handling return values in forms" section for "use-server" docs fails to compile

Summary

The following example is given in Handling return values in forms section for "use server" docs, fails to compile.

// requestUsername.js
'use server';

export default async function requestUsername(formData) {
  const username = formData.get('username');
  // ..
}

// UsernameForm.js
'use client';

import { useActionState } from 'react';
import requestUsername from './requestUsername';

function UsernameForm() {
  const [state, action] = useActionState(requestUsername, null, 'n/a');
  // ..
}

Page

https://react.dev/reference/rsc/use-server#handling-return-values

Details

It fails to compile because, as per the useActionState docs,

useActionState(action, initialState, permalink?)

the "action" (requestUsername in this case) should have previousState as the first argument,
and formData as the second argument.

However, for the above example, the requestUsername action has formData as the first argument,
rather than previousState. Therefore, it fails to compile.

The following is the correct way mentioned in the useActionState docs:

async function increment(previousState, formData) {
  return previousState + 1;
}

function StatefulForm({}) {
  const [state, formAction] = useActionState(increment, 0);
  // ..
}

I can raise a PR for the fix, if it's okay.

从 use-server 页面上链接的“Handling return values in forms”部分开始，将其中的 useActionState 示例与链接的 useActionState 文档进行比较。更新 requestUsername 示例，使其参数与文档中记录的 action 签名匹配，然后验证文档示例能够编译。