Update documents.php

Changed to ellipsis. See https://www.transifex.com/nextcloud/nextcloud/translate/#de_DE/$/102251710?issue=yes

templates/documents.php

@@ -14,7 +14,7 @@ script('richdocuments', 'documents');
 ?>
 <div id="documents-content">
 	<ul class="documentslist">
-		<li class="progress icon-loading"><div><?php p($l->t('Loading documents...')); ?></div></li>
+		<li class="progress icon-loading"><div><?php p($l->t('Loading documents…')); ?></div></li>
 		<li class="document template" data-id="" style="display:none;">
 			<a target="_blank" href=""><label></label></a>
 		</li>