ch06/03 fixes

[d-kleine]

• fixed bash commands in readme
• added missing logreg bash command in readme
• updated help docstrings

[rasbt]

Thanks for the update. Actually, it might be shorter and sufficient to use args.bert_model (updated it in the PR). But good callout!

[d-kleine]

@rasbt Thanks - yeah, I agree, using --model is more straightforward :)

What about the train_bert_hf_spam.py and sklearn-baseline.ipynb files, are they still needed in this folder? For me, it seems like they don't have any purpose in the code for this project anymore.

[rasbt]

Regarding those files, I agree, they are not used in this folder here, but I am preparing a post with some comparisons, and I needed them there, so I'd like to keep them there for reference.

[d-kleine]

Okay thanks