Handle opener tag

src/Controller/Tei2SolrController.php

@@ -929,6 +929,7 @@ class Tei2SolrController extends AbstractController
                         ($element->nodeName === 'p' && $element->firstChild->nodeName !== 'address') ||
                         ($element->nodeName === 'dateline' && 'closer' !== $element->parentNode->nodeName) ||
                         $element->nodeName === 'address' ||
+                        $element->nodeName === 'opener' ||
                         $element->nodeName === 'closer' ||
                         $element->nodeName === 'list' ||
                         ($element->nodeName === 'signed' && 'closer' !== $element->parentNode->nodeName)