`complete-word` not working on windows

[iamkroot]

This is not working on windows-

> usage complete-word --shell powershell -f "$specFile" -- @words mise
Error: xx::process (link)

  × program not found
  │ sh -c mise tasks ls --complete

usage/lib/src/sh.rs

Line 5 in 46e90b4

pub(crate) fn sh(script: &str) -> XXResult<String> {

assumes sh is present everywhere.