enforcing documentation for tested API

developer_manual/digging_deeper/api.rst

@@ -20,10 +20,10 @@ testing version of the future API in the `NCT` namespace, following these rules:
 - Code from the `OCP` namespace must never mention anything coming from the `NCT` namespace. It can not require it as an argument, constant or return something from `NCT`.
 - An API can only live in this testing namespace for one major release.
 - During this testing phase, the code and the API can be modified/restructured without limitation.
+- API within the testing namespace must have up-to-date documentation.
 - If accepted, the API will be copied to the `OCP` public namespace.
 - Once tested, the version from the `NCT` namespace will be marked as deprecated.
 - Deprecated API from the `NCT` namespace are kept for 2 major releases.
 
 .. note::
-  - API within the testing namespace might not have documentation other than in-code comments.
   - API from `NCT` are included to the `nextcloud-deps/OCP` package for easier testing with psalm