feat(cli): add completions command to jstz

[johnyob]

Context

Related Tasks: Shell autocompletions for CLI

Description

This PR adds a completions command to jstz, which prints the autocompletions for the CLI to stdout

Manually testing the PR

Since we don't yet globally install jstz as a binary, it's a bit finicky to test locally.

For zsh:

autoload -U compinit && compinit
source <(cargo run --bin jstz -- completions --shell=zsh)
compdef _jstz ./target/debug/jstz

To use the completions, you must use ./target/debug/jstz [Tab] ([Tab] denotes you pressing tab). I've not been able to get this to work with cargo run --bin jstz -- ...

For other shells:
clap-rs/clap#2488 (comment)

[sam-finch-tezos]

🎉 🥳 Awesome!
Happy to merge on the grounds that merged is better than not merged.
I had to install a couple of things to get it to work

brew install --cask autodmg
brew install compiledb

Could I suggest the following additions (if possible) before you close the ticket

• Add whatever is necessary to our nix to work in the nix-shell
• Add something to the makefile so that target/debug/jstz and target/release/jstz are set up for you.

If that's not possible or a pain to do then don't worry

[johnyob]

Add whatever is necessary to our nix to work in the nix-shell

If you're using direnv (as you ought to be), then the shell is configured externally to nix

Add something to the makefile so that target/debug/jstz and target/release/jstz are set up for you.

This is possible, I can probably set it up for zsh. But perhaps in a different PR?

[ryutamago]

LGTM!

[sam-finch-tezos]

Add something to the makefile so that target/debug/jstz and target/release/jstz are set up for you.

This is possible, I can probably set it up for zsh. But perhaps in a different PR?
Absolutely, just add a note to the ticket and but it back into planned.

[johnyob]

Absolutely, just add a note to the ticket and but it back into planned.

https://app.asana.com/0/1205770721173531/1206520076651987/f