Fields need to be suggested

[AdrienWehrle]

We currently test for the validity of fields in the JSON files and warn the contributor when standards are not met (which is great and needed). However, for the moment we don't propose those options to the contributor at the PR stage. Let's work on that and make it clearer!

• One solution is to have comments in a template JSON file with the different options for each key so it could be used as either a reference for the update of existing files or a starting point for a new object!