languagecode_criterion.md: Another use case

Author: adriendupuis

docs/search/criteria_reference/languagecode_criterion.md

@@ -63,3 +63,23 @@ return $this->render('list/articles_to_translate.html.twig', [
     'articles' => $articles,
 ]);
 ```
+
+You can use the `LanguageCode` Criterion to search in
+several languages while ensuring result have a translation in one language:
+
+```php
+$query = new Query(['query' =>
+    new Criterion\LogicalAnd([
+        new Criterion\FullText($text),
+        new Criterion\LanguageCode(['eng-GB'], false)
+    ])
+]);
+
+$results = $this->searchService->findContent($query, ['eng-GB', 'fre-FR', 'ger-DE']);
+
+foreach ($results->searchHits as $searchHit) {
+    /** @var $content \Ibexa\Core\Repository\Values\Content\Content */
+    $content = $searchHit->valueObject;
+    dump($content->getName('eng-GB'));
+}
+```