Show two options for items in folder array [SA-18729] master

[tomcdonnell]

Overview

This PR corrects the API documentation for the assessments folder filter.

Previously the docs said the folder filter should contain an array like [{"id": integer, "code": string}, ...]

After this PR, the docs say the folder filter should contain an array like [{"id": integer}, {"code": string}, ...]

Shortcomings of Redocly

Although I think the API specification is correct after this PR, the rendering by Redocly is still not quite correct.

Problem 1:

The rendering by Redocly suggests that the folders array should contain an object that contains nested objects. This structure in not valid JSON. Example:

// Invalid JSON:
folders: [{{"id": 80}, {"code": "9ENGA"}, ...}]

What we really want is 'An array of objects, each of which specifies either an "id" or a "code".' Example:

// Valid JSON:
folders: [{"id": 80}, {"code": "9ENGA"}, ...]

I added a text description of how the array should be structured to clarify. What I've done is the best we can do I think.

Problem 2:

Note the blank orange square above the second option for the folder filter (the object-only option). No number appears in that square because I marked that option as deprecated. I think this is a styling bug in Redocly. Since the styling does not make clear that the option is deprecated, I changed the description to '(Deprecated)'.