The `--choose` subcommand runs a chooser to select a recipe to run. The
chooser should read lines containing recipe names from standard input,
and write one of those names to standard output.
The chooser defaults to `fzf`, a popular fuzzy finder, but can be
overridden by setting $JUST_CHOOSER or passing `--chooser <CHOOSER>`.
On Windows, skip conversion if a shebang path does not include `/`. In
this case it is not a Unix path, and does not need to be converted to a
Windows path before running.
