Don't print stdout/stderr in error messages because we already pipe that to console when running the child process

Fixes #422

src/child.rs

@@ -171,7 +171,6 @@ pub fn run(
     if exit.success() {
         return Ok(stdout);
     } else {
-        let msg = format!("`{}` did not exit successfully", command_name);
-        return Err(Error::cli(&msg, stdout.into(), stderr.into(), exit).into());
+        return Err(Error::cli(command_name, stdout.into(), stderr.into(), exit).into());
     }
 }

src/error.rs

@@ -47,13 +47,10 @@ pub enum Error {
     },
 
     /// An error invoking another CLI tool.
-    #[fail(
-        display = "Process exited with {}: {}.\n\nstdout:{}\n\nstderr:\n\n{}",
-        exit_status, message, stdout, stderr
-    )]
+    #[fail(display = "`{}` exited with {}", tool, exit_status)]
     Cli {
         /// Error message.
-        message: String,
+        tool: String,
         /// The underlying CLI's `stdout` output.
         stdout: String,
         /// The underlying CLI's `stderr` output.
@@ -101,9 +98,9 @@ pub enum Error {
 
 impl Error {
     /// Construct a CLI error.
-    pub fn cli(message: &str, stdout: Cow<str>, stderr: Cow<str>, exit_status: ExitStatus) -> Self {
+    pub fn cli(tool: &str, stdout: Cow<str>, stderr: Cow<str>, exit_status: ExitStatus) -> Self {
         Error::Cli {
-            message: message.to_string(),
+            tool: tool.to_string(),
             stdout: stdout.to_string(),
             stderr: stderr.to_string(),
             exit_status,
@@ -161,7 +158,7 @@ impl Error {
               local_minor_version: _,
             } => "Your rustc version is not supported. Please install version 1.30.0 or higher.",
             Error::Cli {
-                message: _,
+                tool: _,
                 stdout: _,
                 stderr: _,
                 exit_status: _,