api_docs: Add table of links for easy navigation in events api docs.

[Vector73]

This first commit adds a table of links for easy navigation of events in API documentation.
The second commit converts the event names in API documentation to lowercase.

Self-review checklist

• Self-reviewed the changes for clarity and maintainability
  (variable names, code reuse, readability, etc.).

Communicate decisions, questions, and potential concerns.

• Explains differences from previous plans (e.g., issue description).
• Highlights technical choices and bugs encountered.
• Calls out remaining decisions and concerns.
• Automated tests verify logic where appropriate.

Individual commits are ready for review (see commit discipline).

• Each commit is a coherent idea.
• Commit message(s) explain reasoning and motivation for changes.

Completed manual review and testing of the following:

• Visual appearance of the changes.
• Responsiveness and internationalization.
• Strings and tooltips.
• End-to-end functionality of buttons, interactions and flows.
• Corner cases, error conditions, and easily imagined bugs.

[timabbott]

Is it easy to write this using a Jinja2 template (i.e. the things under templates/) instead? Generally our policy is for HTML to be done in templates unless there's a very good reason to do something different.

[timabbott]

Might be something we should leave to a follow-up, since this file doesn't use those as a general pattern.

[timabbott]

Shouldn't CSS grid be able to just show as many columns as there are space for, without all these media queries?

[Vector73]

I tried it but was having trouble getting everything in place. The items were arranged horizontally instead of vertically.