Add support for bigint to pretty-format

[msafi]

Summary

I was experimenting with BigInt numbers and noticed that Jest will not print these correctly in diffs. For example, for

const f = {
  a: BigInt(1),
  b: BigInt(2)
}

Jest would print the diff something like

Received: f {a: {}, b: {}}
Expected: f {a: {}, b: {}}

because pretty-format thinks BigInt is an object.

I made BigInts print with an n appended, like they print in the browser and Node so that the above would print something like this instead

Received: f {a: 1n, b: 2n}
Expected: f {a: 2n, b: 1n}

Test plan

I added unit tests that mimic the unit tests for number types.

[facebook-github-bot]

Thank you for your pull request and welcome to our community. We require contributors to sign our Contributor License Agreement, and we don't seem to have you on file. In order for us to review and merge your code, please sign up at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need the corporate CLA signed.

If you have received this in error or have any questions, please contact us at [email protected]. Thanks!

[facebook-github-bot]

Thank you for signing our Contributor License Agreement. We can now accept your code for this (and any) Facebook open source project. Thanks!

[SimenB]

Thanks! I left a couple of inline comments to make CI happy.

Beyond those, can you update the chnagelog?

[jeysal]

Cool! LGTM after addressing Simen's comments

[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.
Please note this issue tracker is not a help forum. We recommend using StackOverflow or our discord channel for questions.