Isolation Forest - Max Depth Documentation

**Description**
When fitting an Isolation Forest, the `max_depth` is implicitly defined by the `max_samples` parameter. (Seen [here](https://github.com/scikit-learn/scikit-learn/blob/a86709fdc379f7d7db76a75f39572890e4ddcad1/sklearn/ensemble/iforest.py#L262)). The documentation could provide more transparency on this relationship.