Consumers should not parse problem title and detail

[jpraet]

The problem RFC explicitly states in https://www.rfc-editor.org/rfc/rfc9457.html#section-3.1.4:

Consumers SHOULD NOT parse the "detail" member for information; extensions are more suitable and less error-prone ways to obtain such information.

Could we highlight that in the Belgif REST Guidelines, and also make it applicable to the "title" property + to issue detail/title?

This to avoid the scenario where API providers are blocked from making cosmetic changes or typo fixes in problem title / detail messages because it could be potentially breaking for API consumers.

[pvdbosch]

WG: We'll add a line to [err-problem] to explicitly indicate that title and detail should not be parsed; and additional properties may be added to provide more structured information on the problem