PXP-371: CLI should support autocomplete for the commands

[jk-gan]

Ticket: PXP-371

Changelog

New

• wukong completions <SHELL> command to generate wukong completions for user's shell at runtime
• add a shell script (generate-completions.sh) to generate wukong completions (it should be useful for CI/CD)

Screenshot

[onimsha]

It not working properly on my end.

My current env:

❯ zsh --version
zsh 5.8 (x86_64-apple-darwin20.1.0)

Loading the completion in ZSH shell throws this error.

❯ source <(./target/debug/wukong completions zsh)
_arguments:comparguments:325: can only be called from completion function

Also running the generate-completions.sh scripts throws some error.

❯ ./generate-completions.sh
error: Found argument 'completions' which wasn't expected, or isn't valid in this context

USAGE:
    wukong [OPTIONS] <SUBCOMMAND>

For more information try --help
bash completions generated successfully at /Users/tuanco/code-workspaces/rust/src/github.com/mindvalley/wukong-cli/completions/bash/wukong.bash.
error: Found argument 'completions' which wasn't expected, or isn't valid in this context

USAGE:
    wukong [OPTIONS] <SUBCOMMAND>

For more information try --help
zsh completions generated successfully at /Users/tuanco/code-workspaces/rust/src/github.com/mindvalley/wukong-cli/completions/zsh/_wukong.
error: Found argument 'completions' which wasn't expected, or isn't valid in this context

USAGE:
    wukong [OPTIONS] <SUBCOMMAND>

For more information try --help
fish completions generated successfully at /Users/tuanco/code-workspaces/rust/src/github.com/mindvalley/wukong-cli/completions/fish/wukong.fish.

[jk-gan]

According to starship/starship#2806, we will have to replace the last line from the zsh completion generated by clap in order to let the completion source-able.

I've added the replacement in the generate-completions.sh.