In case of ng completion, display the warning text to stderr and exit with return code 1.

Author: catull

packages/@angular/cli/bin/ng

@@ -155,20 +155,20 @@ resolve('@angular/cli', { basedir: process.cwd() },
       }
 
       if (shouldWarn && CliConfig.fromGlobal().get('warnings.versionMismatch')) {
-        let warning = stripIndents`
+        let warning = yellow(stripIndents`
           Your global Angular CLI version (${globalVersion}) is greater than your local
           version (${localVersion}). The local Angular CLI version is used.
 
           To disable this warning use "ng set --global warnings.versionMismatch=false".
-        `;
+        `);
          // Don't show warning colorised on `ng completion`
          if (process.argv[2] !== 'completion') {
            // eslint-disable no-console
-           console.log(yellow(warning));
+           console.log(warning);
          } else {
-           warning = warning.replace(/^/gm, '# ');
            // eslint-disable no-console
-           console.log(warning);
+           console.error(warning);
+           process.exit(1);
          }
       }