LanguageFormatter is not used for nodes because it's still hard coded in NodeViewBuilder

Other tweaks. I've used the latest PR from #85

Closes #2637808

core/modules/language/src/Hook/LanguageHooks.php

@@ -3,7 +3,9 @@
 namespace Drupal\language\Hook;
 
 use Drupal\Core\Access\AccessResultInterface;
+use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
 use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\language\EntityViewDisplayConfigUpdater;
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrlFallback;
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrl;
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUI;
@@ -30,6 +32,10 @@ class LanguageHooks {
 
   use StringTranslationTrait;
 
+  public function __construct(
+    private readonly EntityViewDisplayConfigUpdater $languageConfigUpdater,
+  ) {}
+
   /**
    * Implements hook_help().
    */
@@ -380,4 +386,14 @@ public function languageTypesInfoAlter(array &$language_types): void {
     ];
   }
 
+  /**
+   * Implements hook_ENTITY_TYPE_presave().
+   */
+  #[Hook('entity_view_display_presave')]
+  public function entityViewDisplayPresave(EntityViewDisplayInterface $entityViewDisplay): void {
+    if ($entityViewDisplay->isSyncing()) {
+      $this->languageConfigUpdater->updateEntityViewDisplay($entityViewDisplay);
+    }
+  }
+
 }