Add new id field to event docs

[velvia]

@randall-Mysten is this needed for 0.15.1 release?

[randall-Mysten]

It would be nice to include if the code changes are included in the re

@randall-Mysten is this needed for 0.15.1 release?

It would be nice to include if the code changes are included in the release. Thanks for making the update

[velvia]

@randall-Mysten the code changes are part of 0.15.1. I do need you to approve though so I can merge it. Thanks!