remove unnecessary label

packages/app/resource/locales/en_US/translation.json

@@ -383,9 +383,6 @@
       "no_deadline":"This page has no expiration date"
     }
   },
-  "page_table_of_contents": {
-    "empty": "Table of Contents is empty"
-  },
   "page_edit": {
     "Show active line": "Show active line",
     "auto_format_table": "Auto format table",

packages/app/resource/locales/ja_JP/translation.json

@@ -382,9 +382,6 @@
       "no_deadline": "このページに有効期限は設定されていません。"
     }
   },
-  "page_table_of_contents": {
-    "empty": "目次は空です"
-  },
   "page_edit": {
     "Show active line": "アクティブ行をハイライト",
     "auto_format_table": "表の自動整形",

packages/app/resource/locales/zh_CN/translation.json

@@ -369,9 +369,6 @@
 			"conflict": "无法保存您所做的更改，因为其他人正在编辑此页。请在重新加载页面后重新编辑受影响的部分。"
 		}
   },
-  "page_table_of_contents": {
-    "empty": "目录为空"
-  },
   "page_comment": {
     "display_the_page_when_posting_this_comment": "Display the page when posting this comment"
   },

packages/app/src/components/TableOfContents.jsx

@@ -74,7 +74,6 @@ const TableOfContents = (props) => {
             id="revision-toc-content"
             className="revision-toc-content mb-2"
           >
-            <span className="text-muted">({t('page_table_of_contents.empty')})</span>
           </div>
         ) }