[Typo]: Missing underscore in unstable_Activity import

[guillaumebrunerie]

Summary

The unstable_Activity import is missing an underscore.

Page

https://react.dev/reference/react/Activity#activity

Details

It should be

import {unstable_Activity as Activity} from 'react';

instead of

import {unstableActivity as Activity} from 'react';

[tusharagrawall]

Assign this issue to me please @guillaumebrunerie