Write resolved entity-field references with their own field type in Markdown #2602

Part of #2425 (F-API). A follow-up from the review of #2571.

A reference to an entity field holds the resolved published value in the Markdown representation. That value is written with the page's own field type, reference, so it goes through plain-text escaping. When the referenced fact is rich text, such as a product's description shown on its page, its formatting is lost and the asterisks appear as characters.

Scope

• Write a resolved entity-field reference with the type of the field it points at, read from the definition of the version the value came from. Rich text is quoted as it is for the page's own rich text fields.
• Keep the definitions read in a fixed number of queries.

Acceptance

• A page that references a product's rich text description shows it as quoted rich text, and a number or text fact reads as it does today.
• The tests pass on both providers.