only in patch2:
unchanged:
--- a/core/modules/search/search.install
+++ b/core/modules/search/search.install
@@ -154,3 +154,13 @@ function search_requirements($phase) {
 
   return $requirements;
 }
+
+/**
+ * Mark everything for reindexing after diacritics removal rule change.
+ */
+function search_update_9000() {
+  $search_page_repository = \Drupal::service('search.search_page_repository');
+  foreach ($search_page_repository->getIndexableSearchPages() as $entity) {
+    $entity->getPlugin()->markForReindex();
+  }
+}