[feature] Shell completions

[Freed-Wu]

Like https://docs.iterative.ai/shtab/? TIA!

• https://github.com/andreafrancia/trash-cli/blob/master/setup.cfg#L31-L33
• https://github.com/inducer/pudb/blob/main/setup.py#L28
• https://github.com/piccolomo/plotext/blob/master/setup.py#L25
• https://github.com/wookayin/gpustat/blob/master/setup.py#L114

[daniel-jones-deepl]

Hi @Freed-Wu wzy, thanks for the suggestion, and the examples.

This is a great suggestion, it would make sense to add this feature to the CLI sometime.