Function exit_code_desc 

pub fn exit_code_desc(code: &Option<i32>) -> String

Render a process exit code for an operator, without the Some(1) Debug leak the old {code:?} interpolation produced.

use kopiur_kopia::humanize::exit_code_desc;
assert_eq!(exit_code_desc(&Some(1)), "exit code 1");
assert_eq!(exit_code_desc(&None), "no exit code (process killed by a signal)");