Fix typo in the default value of dict_key_x

[wiseodd]

Change the default from inputs_id to input_ids, which is the default of Huggingface.

Based on wiseodd/llm-bayesopt-exps#2

[aleximmer]

Is there any changes to the docs that has to be reviewed or is it just because of some version change?

[runame]

Same question as Alex's.

[wiseodd]

Thanks! The docs are fine --- I double-checked it.