JSON values in examples are rendered as Python dicts

[chad-earthscope]

JSON values for examples such as:

          "examples": [
            {
              "header1": "Value of header1",
              "header2": "Value of header2",
              "header3": 99.4
            }
          ]

are rendered as Python dict types, which is close but not valid JSON.

The original code had a mechanism for the caller to specify the format of the examples (but it was not the style we want); it could be reintroduced for the item details printing of examples.