Add nushell completions

[j-xella]

hyperfine comes with completions files for bash, zsh, fish, powershell ....

Can nushell have some love too?

[sharkdp]

It does not seem to be supported by clap_complete at the moment: https://docs.rs/clap_complete/latest/clap_complete/aot/enum.Shell.html

Closing this for now (until upstream supports this potentially)

[RGBCube]

There exists a clap_complete_nushell crate that's in the clap repo and cratesio that provides this functionality.

The reason why it isn't in the main crate seems to be because Nushell isn't stable yet, but the stuff generated by it won't be changed any time soon.

Could that crate be integrated into the build.rs?

[sharkdp]

Could that crate be integrated into the build.rs?

Sure.