Issue #2872355 by sarguna raj M, chiranjeeb2410, joachim: expand and clarify...

Issue #2872355 by sarguna raj M, chiranjeeb2410, joachim: expand and clarify docs for DefaultPluginManager::alterInfo()

core/lib/Drupal/Core/Plugin/DefaultPluginManager.php

@@ -156,7 +156,7 @@ public function setCacheBackend(CacheBackendInterface $cache_backend, $cache_key
   }
 
   /**
-   * Initializes the alter hook.
+   * Sets the alter hook name.
    *
    * @param string $alter_hook
    *   Name of the alter hook; for example, to invoke