Okay, I read several articles and this is my conclusion:
- the "Rocher du Vieux Bon Dieu" (not rocherS) is the rock that King Albert fell from.
- "Rocher du Vieux Bon Dieu" was named "Rocher du Roi Albert" in his honor.
Therefore, the name is Rocher du Roi Albert, but I put Rocher du Vieux Bon Dieu as alt_name because people also know it as this.

Also: the rock to the north-west was named "Rocher du Roi Albert" but has nothing to do with any of this. I don't think it should be on the map.

If this is not okay in some way, please correct.

https://www.openstreetmap.org/changeset/167048893#map=19/50.482087/4.948378&layers=D