Assure credential-helpers show their error stream in the terminal.

This restores the previous behaviour, which by default is disabled now.

Author: Byron

src/plumbing/main.rs

@@ -13,6 +13,7 @@ use gitoxide::shared::pretty::prepare_and_run;
 use gitoxide_core as core;
 use gitoxide_core::{pack::verify, repository::PathsOrPatterns};
 use gix::bstr::{io::BufReadExt, BString};
+use gix::config::tree::Key;
 
 use crate::plumbing::{
     options::{
@@ -107,6 +108,14 @@ pub fn main() -> Result<()> {
                 } else {
                     opts.cli_overrides(config.clone())
                 }
+                .config_overrides([
+                    gix::config::tree::gitoxide::Credentials::HELPER_STDERR
+                        .validated_assignment_fmt(&true)
+                        .expect("valid boolean value"),
+                    gix::config::tree::gitoxide::Core::EXTERNAL_COMMAND_STDERR
+                        .validated_assignment_fmt(&true)
+                        .expect("valid boolean value"),
+                ])
             };
             mapping.full.modify(to_match_settings);
             mapping.reduced.modify(to_match_settings);