transformers

daf520b0 - tiny tweak to allow BatchEncoding.token_to_char when token doesn't correspond to chars (#15901)

tiny tweak to allow BatchEncoding.token_to_char when token doesn't correspond to chars (#15901) * tweak to allow BatchEncoding.char_to_token(0) * update docstring * remote trailing whitespace * make fixup * make value checking for span_indices explicit Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com> Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>