Add example for `reloo()`

[jordandeklerk]

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We don't have an example in the docstring for reloo() currently because it was getting too complicated. We should add a comprehensive example here. I know that when I used reloo() in legacy ArviZ a while back, I had trouble implementing a proper sampling wrapper to actually use the function. I think it would be beneficial to develop a realistic, in-depth example for this to guide users in the right direction.