Correct comment

src/Plugin/PdfBackendManager.php

@@ -12,7 +12,7 @@ use Drupal\Core\Extension\ModuleHandlerInterface;
 class PdfBackendManager extends DefaultPluginManager {
 
   /**
-   * Constructs a new BackendServiceManager object.
+   * Constructs a new PdfBackendManager object.
    *
    * @param \Traversable $namespaces
    *   An object that implements \Traversable which contains the root paths