Add act documentation

[jackpope]

Content from legacy docs https://legacy.reactjs.org/docs/test-utils.html#act

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
19-react-dev	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	May 24, 2024 4:20pm
react-dev	✅ Ready (Inspect)	Visit Preview		May 24, 2024 4:20pm

[rickhanlonii]

Can you update this to match our other Reference pages?

The top section should be a one-line short description, followed by a psudoish code example, and a TOC:

Then a Reference with a short example, parameters, returns, and caveats

Then a usage section with headings that explain the use case and are visible in the right sidebar:

Then a troubleshooting section:

We can defer the troubleshooting section, but it would include things like not using await or not setting the IS_ACT_ENV global.

[rickhanlonii]

And can we change the base branch to main? Since this was added to 18.3, it should be added to those docs. I'll merge it into the v19 branch

[github-actions]

Size changes

Details

📦 Next.js Bundle Analysis for react-dev

This analysis was generated by the Next.js Bundle Analysis action. 🤖

One Page Changed Size

The following page changed size from the code in this PR compared to its base branch:

Page	Size (compressed)	First Load
/[[...markdownPath]]	82.63 KB(🟡 +6 B)	186.78 KB

Details

Only the gzipped size is provided here based on an expert tip.

First Load is the size of the global bundle plus the bundle for the individual page. If a user were to show up to your website and land on a given page, the first load size represents the amount of javascript that user would need to download. If next/link is used, subsequent page loads would only need to download that page's bundle (the number in the "Size" column), since the global bundle has already been downloaded.

Any third party scripts you have added directly to your app using the <script> tag are not accounted for in this analysis

Next to the size is how much the size has increased or decreased compared with the base branch of this PR. If this percentage has increased by 10% or more, there will be a red status indicator applied, indicating that special attention should be given to this.