Make sure document event listener will specify more specific type - readystatechange

[jurosh]

Make sure document event listener will specify more specific type for readystatechange #41775

Please verify that:

• There is an associated issue in the Backlog milestone (required)
• Code is up-to-date with the master branch
• You've successfully run gulp runtests locally
• There are new or updated unit tests validating the change

Fixes #

#41775

[typescript-bot]

It looks like you've sent a pull request to update our 'lib' files. These files aren't meant to be edited by hand, as they consist of last-known good states of the compiler and are generated from 'src'. Unless this is necessary, consider closing the pull request and sending a separate PR to update 'src'.

[typescript-bot]

It looks like you've sent a pull request to update some generated declaration files related to the DOM. These files aren't meant to be edited by hand, as they are synchronized with files in the TSJS-lib-generator repository. You can read more here. For house-keeping purposes, this pull request will be closed.

[typescript-bot]

This PR doesn't have any linked issues. Please open an issue that references this PR. From there we can discuss and prioritise.