transformers

5c84682f - Customise the separator used for splicing in DataCollatorWithFlattening (#33114)

Customise the separator used for splicing in DataCollatorWithFlattening (#33114) * Customising the separator used for splicing in DataCollatorWithFlattening * update DataCollatorWithFlattening docs --------- Co-authored-by: weifangyuan <i.weifangyuan@yuewen.com>