tidied up the class names

src/Event/SolrDocumentAlterSubscriber.php

@@ -24,10 +24,10 @@ class SolrDocumentAlterSubscriber implements EventSubscriberInterface {
   /**
    * Alters the Solr document before it is sent to Solr.
    *
-   * @param \Drupal\search_api_solr\Event\SolrDocumentAlterEvent $event
+   * @param \Drupal\search_api_solr\Event\SearchApiSolrEvents $event
    *   The Solr document alter event.
    */
-  public function alterSolrDocument(SolrDocumentAlterEvent $event) {
+  public function alterSolrDocument(SearchApiSolrEvents $event) {
     $solrDocument = $event->getSolrDocument();
     $item = $event->getItem();
     $index = $event->getIndex();