Remove pretty print in example

Hello!

I would like to have a human-readable documentation with asciidoctor and a machine-readable documentation with this project. Is there a possibility to disable or un-pretty-print the JSON only for the resource.json?

I know of the possibility of Preprocessor but with this, I can only control both versions of the documentation.

For now, the example in the resource.json and the resulting .yml is riddled with escape and whitespace characters and when imported in postman, it's also shown there. It is impossible to use postman with the imported documentation, without removing these control elements beforehand. This is also shown in the [README.md](https://github.com/ePages-de/restdocs-api-spec#usage-with-spring-rest-docs)