Readme: WeakRef and FinalizationRegistry now widely supported

[Taro]

README.md states:

The Record and Tuple polyfill requires several JavaScript features that are only available experimentally in browsers, specifically WeakRef and FinalizationRegistry.

And then cites Chrome Canary ans the only browser supporting these features out of the box.

This was last updated 2 years ago, apparently.

Per canisue.com, these have been supported in the leading browsers for more than 2 years:

• https://caniuse.com/?search=WeakRef
• https://caniuse.com/?search=FinalizationRegistry

Would it make sense to remove the Supported Environments/Browsers section entirely?

[Matthew Dean]

It's also widely supported in Node.js as well (v14+).

It's a shame this polyfill isn't being maintained, as this is a feature a lot of people are excited about.