Return cross-attention weights in generation function
# 🚀 Feature request

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With v4.2.0 release, generation can now return encoder and decoder self-attention weights but it still doesn't return cross-attention weights. These weights are already computed and returned in model `forward` method, and just need to be returned in `generate` method.
## Motivation

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Visualizing cross-attention weights is useful for many applications such as token-alignment.

## Your contribution

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I can submit a PR.

Hi @patrickvonplaten!
Please let me know what you think about the feature. I can send a PR for it once you confirm.<|||||>Yes, this would be a nice addition indeed :-)<|||||>Happy to help you in your PR!