Ability to specify multiple classes in class_ for ClassSelector parameter type needs to be documented

I stumbled upon the ability to input a tuple into ClassSelector by querying Perplexity to scour the documentation and API.
e.g.
```python
class Test(Parameterized):
    test_param = param.ClassSelector(class_=(dict, list))
```

It would probably be a big benefit to document this feature.
The only place I found it mildly mentioned was in the Deprecations section of the Upgrade Guide.