ForTokenClassification head on BART
# 🚀 Feature request

Hello guys! I'm trying to reproduce the token classification experiments from the [BART paper](https://arxiv.org/abs/1910.13461) using the HF/Transformers and found that a token classification head is missing on the current BART model HF implementation. 

The current BART implementation only has the "BartForConditionalGeneration" and "BartForSequenceClassification". Are there any plans to add a "BartForTokenClassification" head too? 

It would be great to have a `BartForTokenClassification`. Does it use the same head as `BertForTokenClassification`, etc.? 

Feel free to open a PR :) <|||||>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.

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