Non unique error message showing field machine name instead of field label

The error message showing the field machine name which is not user friendly. In fact, the field label could be in a different language.
Here is an example how to change the error message. (For a node validation).

+$fieldInfo = \Drupal\field\Entity\FieldConfig::loadByName('node', $form['bundle'], $field_name);
+$fieldLabel = $fieldInfo->getLabel();
-$form_state->setErrorByName($field_name, t('The field @field_name has to be unique.', array('@field_name' => $field_name)));
+$form_state->setErrorByName($field_name, t('The field @field_name has to be unique.', array('@field_name' => $fieldLabel)));