Add displaCy data structures to docs (2)

[svlandeg]

PR redone from #12202 to target master instead of v4.

Description

This PR adds a new section to the api/top-level#functions documentation for displaCy: Visualizer data structures. The section shows examples of the three data structures (Dependency Parsing, Entity Recognition, and Span Classification) and their types formatted as tables. To reduce cluttering, the nested dictionary types are formatted as a collapsable table.

The idea for this PR initially came from this discussion #10950
The types are based on this gist by @pmbaumgartner

Types of change

Documentation

Checklist

• I confirm that I have the right to submit this contribution under the project's MIT license.
• I ran the tests, and all new and existing tests passed.
• My changes don't require a change to the documentation, or if they do, I've added all required information.

[svlandeg]

Thanks for your work on this, @thomashacker!