Translate /src/assets/locales/ja.json in zh_TW

translation completed for the source file '/src/assets/locales/ja.json'
on the 'zh_TW' language.

Author: transifex-integration[bot]

src/assets/locales/zh_TW.json

@@ -70,12 +70,16 @@
         "time": "設定時間",
         "subject_label_color": "標籤顏色",
         "description": "詳細說明",
+        "video_keyword": "可選功能（影片搜尋）",
         "video_url": "參考影片 URL",
         "video_thumbnail": "顯示影片縮圖",
         "textbook_page": "教科書頁",
         "material_title": "副教材標題",
         "material_url": "輔助教材 URL"
       },
+      "placeholders": {
+        "video_keyword": "例）理科"
+      },
       "required": "*符號者為必填項目"
     },
     "editing_visibility_dialog": {