Events API documentation should reference Discussions documentation
<!--
* Use this issue template for suggesting new docs or updates to existing docs.
Note: Doc work as part of feature development is covered in the Feature Request template.
* For issues related to features of the docs.gitlab.com site, see
https://gitlab.com/gitlab-org/gitlab-docs/issues/
* For information about documentation content and process, see
https://docs.gitlab.com/ee/development/documentation/ -->
### Problem to solve
I spent some time trying to work out how to get events relating to an issue being added to / removed from a given milestone. Only after inspecting the gitlab page did I find it exists as discussions.json - which lead me to the [Discussions API](https://docs.gitlab.com/ee/api/discussions.html). "Discussions" seems an odd name for this data - perhaps the [Events API](https://docs.gitlab.com/ee/api/events.html) page could include a summary of other "event" related APIs that the user might also want to look at. (E.g. as well as discussions, audit events would be worth highlighting)
### Further details
### Proposal
Summary table on the "Events API" page of "other APIs that have event related information", with examples of the kind of things that are listed there.
### Who can address the issue
<!-- What if any special expertise is required to resolve this issue? -->
### Other links/references
<!-- E.g. related GitLab issues/MRs -->
issue