fix i18n bug

resource/locales/en_US/translation.json

@@ -47,7 +47,7 @@
   "Timeline View": "Timeline",
   "History": "History",
   "attachment_data": "Attachment Data",
-  "No attachments yet.": "No attachments yet.",
+  "No attachments yet": "No attachments yet",
   "Presentation Mode": "Presentation",
   "Not available for guest": "Not available for guest",
   "Create Archive Page": "Create Archive Page",

resource/locales/ja_JP/translation.json

@@ -48,7 +48,7 @@
   "Timeline View": "タイムライン",
   "History": "更新履歴",
   "attachment_data": "添付データ",
-  "No attachments yet.": "No attachments yet.",
+  "No attachments yet": "No attachments yet",
   "Presentation Mode": "プレゼンテーション",
   "Not available for guest": "ゲストユーザーは利用できません",
   "Create Archive Page": "アーカイブページの作成",

src/client/js/components/PageAttachment.jsx

@@ -117,7 +117,7 @@ class PageAttachment extends React.Component {
 
     const { t } = this.props;
     if (this.state.attachments.length === 0) {
-      return t('No attachments yet.');
+      return `${t('No attachments yet')}.`;
 
     }