i18n(zh_TW): Update ChineseTaiwan translations

UI/MailPartViewers/ChineseTaiwan.lproj/Localizable.strings

@@ -34,8 +34,6 @@ reply_info = "這是您發起的事件的出席回覆。";
 "to" = "到";
 "Untitled" = "無主旨";
 "Size" = "大小";
-"Digital signature is not valid" = "無效的數位簽章";
-"Message is signed" = "郵件已數位簽章";
 "Subject" = "主旨";
 "From" = "寄件人";
 "Date" = "日期";
@@ -48,3 +46,4 @@ reply_info = "這是您發起的事件的出席回覆。";
 "Cancel" = "取消";
 "OK" = "OK";
 "Comment" = "備註";
+"Description" = "Description";