[scikit-learn] sample_weight for cohen_kappa_score

[Poughon Victor]

Hello,

I'd like to use samples weights together with sklearn.metrics.cohen_kappa_score,
in a similar way to other metrics which have this argument. Is it as simple as
forwarding the weights to the confusion_matrix call? [0]

If yes I'm happy to work on the pull request.

In that case the other argument "weights" might be confusing but it's too late
to rename it, right?

Cheers,

Victor Poughon

[0] https://github.com/scikit-learn/scikit-learn/blob/dee786a/sklearn/metrics/classification.py#L331