Placerholder Text in docs

![Image](https://github.com/user-attachments/assets/37f76687-b5de-478c-9496-e7d9acbaa271)

[Link](https://elliot.readthedocs.io/en/latest/guide/recommenders/unpersonalized.html?highlight=random#module-elliot.recommender.unpersonalized.random_recommender.Random)

There is still placeholder text in the documentation, fyi.

BR,
Gwen