QSocCliWorker: Add the real showError function

- Added the `showError` function to handle displaying error messages and
  setting the exit code without showing help text.
- Modified documentation comments to reflect the addition and purpose of the
  `showError` function.

Signed-off-by: Huang Rui <[email protected]>

src/cli/qsoccliworker.cpp

@@ -79,6 +79,13 @@ bool QSocCliWorker::showErrorWithHelp(int exitCode, const QString &message)
     return false;
 }
 
+bool QSocCliWorker::showError(int exitCode, const QString &message)
+{
+    qCritical().noquote() << message;
+    this->exitCode = exitCode;
+    return false;
+}
+
 bool QSocCliWorker::showInfo(int exitCode, const QString &message)
 {
     qInfo().noquote() << message;

src/cli/qsoccliworker.h

@@ -256,6 +256,16 @@ public slots:
      */
     bool showErrorWithHelp(int exitCode, const QString &message);
 
+    /**
+     * @brief Show error message and emit exit with exitCode.
+     * @details This function will show error message and emit exit with
+     *          exitCode.
+     * @param exitCode The exit code to emit.
+     * @param message The error message to show.
+     * @return bool always false.
+     */
+    bool showError(int exitCode, const QString &message);
+
     /**
      * @brief Show info message and emit exit with exitCode.
      * @details This function will show info message and emit exit with