v3.3 trial balloon: JSON-Compatible Data section

[handrews]

• Addresses TOON support in OpenAPI 3.3? #5140 (beyond putting text/toon in the media type registry, which has already been done).

There's a bit of a question if we want to mention TOON in the spec because of the LLM connection and its use in LLM-related HTTP APIs. I was looking for where to put it and noticed the "JSON Data" and "Non-JSON Data" sections, and thought maybe a "JSON-Compatible Data" section would fit in between them.

Pros of this approach:

• It is a valid class of formats that doesn't quite fit either section
• It lets us treat TOON as one of several things rather than promoting it specifically in a way that might seem dated in another year or two

Cons of this approach:

• Unlike our sections on text/event-stream, multipart, and form-urlencoded, TOON would not appear in the Table of Contents
• The other examples here (TOML and YAML) are popular formats, but not ones that are all that frequently used in HTTP APIs as far as I know (although obviously we use YAML for authoring OADs), so I'm not sure we want to call attention to them here (this is why they're not in the Media Type Registry- I did consider including them and decided not to).

Additional questions:

• Should the format name (TOON, TOML, YAML) and acronym expansions (Token-Oriented Object Notation, Tom's Obvious Minimal Language, YAML Ain't a Markup Language) be included in addition to the media types?

I'm fine with this going in, or reworking it substantially, or dropping the idea and closing #5140 as completed based on the media type registry entry. But I figured it would be easier to discuss a concrete change than the abstract.

• no schema changes are needed for this pull request