Previously, the document fields in an XML payload, the request or
response had to have an application/xml content type. This prevented
documenting standard XML content types such as text/xml and
application/rss+xml as well as payloads with custom XML content types.
This commit updates the logic that sets up the ContentHandler to
first attempt to parse the content as JSON. If that fails it then
parses it as XML. If that fails an exception is thrown. This allows
any JSON or XML content, irrespective of the actual content type, to
be documented.
Closes gh-393
113976f2d9