eZ\Bundle\EzPublishCoreBundle\DependencyInjection\Configuration\Suggestion\Collector\SuggestionCollectorInterface::addSuggestion PHP Method

    public function addSuggestion(ConfigSuggestion $suggestion);

 public function mapConfig(array &$scopeSettings, $currentScope, ContextualizerInterface $contextualizer)
 {
     if (isset($scopeSettings['imagemagick'])) {
         $suggestion = new ConfigSuggestion('"imagemagick" settings are deprecated. Just remove them from your configuration file.');
         $this->suggestionCollector->addSuggestion($suggestion);
     }
 }