Add completion files for bash and zsh

[aartoni]

No more typing full movie names to rate or manage your collection! This PR introduces intelligent autocompletion for mtracker commands, providing suggestions based on context. Here's a breakdown of the new autocomplete behaviors:

• add | a
  • Suggests movie titles from the database
  • Once a movie is specified, suggests --tag
• remove | rm
  • Suggests movie titles from the database
• rate | r
  • Suggests unrated movie titles from the database
  • After selecting a movie, suggests ratings from 0 to 9
• unrate | u
  • Suggests rated movie titles from the database
• list | ls
  • Suggests --tag and --year

Testing

Source the appropriate shell completion script (completions/zsh or completions/bash) and use tab completion on mtracker subcommands to verify suggestions are working as described.

Limitations

Bash lacks built-in support for displaying detailed argument descriptions and for suggesting strings that contain spaces. As a result, Bash completion is limited to simpler cases without complex suggestions.

[r-unruh]

Thanks! This is very interesting and I like it so far.

A few things to fix:

• I'd prefer spaces (4) over tabs here. Just so it's consistent with the Rust code.
• I think the rate command should also include already rated items, since I might want to change a rating.
• Bug: The unrate command includes "WL:" in the name of rated items that are on the watchlist (I might want to rewatch a movie I already know).

By the way, have you seen clap_complete? I've not looked into it yet, but it might bring interesting things to the table.

[aartoni]

You're definitely right on all three points, I've committed the changes. I didn't know about clap_complete and I'd be more than happy to add it to the project to avoid having to update these files manually.

Should we get this merged and create an issue for clap_complete? I won't be able to work on clap_complete today but I might be this weekend or next week.