Incomplete padding support for Funnel Transformer.
Looks like there's a tiny bug in the funnel transformer implementation.
https://github.com/huggingface/transformers/blob/39249c9589f5eb9677807e74221e2eb3ea1b4a35/src/transformers/models/funnel/modeling_funnel.py#L783

Should be:
```python
module.word_embeddings.weight.data[module.word_embeddings.padding_idx].zero_()
```

Though a `pad_token_id` is not a field in `FunnelConfig` the `FunnelEmbeddings` do use the field if its present in the config.

I could make a PR to fix the line & add a usually assign `config.pad_token_id  = None`?
This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.