Type Issue in Documentation

[SCasarotto]

I 100% understand this isn't the right place for this but couldn't seem to get a response or update through the normal https://firebase.google.com/docs Send Feedback flow.

This PR is being held open until the official firebase docs match.

The issue:
Type definition described here (Specifically cancelCallbackOrContext ? : Object | null ) are inaccurate and should match the actual type definition file here.

Sorry to bug but hope this can get resolved. Thanks

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[hsubox76]

This is the correct place for reference docs errors! We currently generate reference docs from packages/firebase/index.d.ts. Hopefully soon they will be generated directly from the code. Made a PR:

#4259

After that is checked in, we need to run our doc generation script and push it to our docs site. I will try to keep the issue open until that part is done.

[hsubox76]

Merged the fix, still need to regenerate docs and push to docs site.

[hsubox76]

Doc page is updated: https://firebase.google.com/docs/reference/js/firebase.database.Query#on