* Add colorized output option to generate script
Two new functions were added to the script that allow output to be colorized based on the T[0] probability. Changes were made to the `generate_step` function in utils.py to permit colorization. Additionally, an argument for colorization was introduced to the command-line parser.
* Rename 'colorize' parameter with 'return_probability' in generate_step
* refactor(qwen): moving qwen into mlx-lm
* chore: update doc
* chore: fix type hint
* add qwen model support in convert
* chore: fix doc
* chore: only load model in quantize_model
* chore: make the convert script only copy tokenizer files instead of load it and save
* chore: update docstring
* chore: remove unnecessary try catch
* chore: clean up for tokenizer and update transformers 4.37
* nits in README
---------
Co-authored-by: Awni Hannun <awni@apple.com>
