【fix】【签名】一级工具栏签名工具，鼠标悬浮没有Tooltips，其他工具都有

PDF Office/PDF Master/Class/PDFWindowController/Toolbar/KMToolbarViewController.swift

@@ -1566,7 +1566,7 @@ extension KMToolbarViewController {
         } else if identifier == KMDocumentSignToolbarItemIdentifier {
             item?.image = NSImage(named: "DigitalSign_icon")
             item?.target = self
-//            item?.toolTip = NSLocalizedString("Digital signature ensures the authenticity and integrity of digital files. Click and drag the cursor to create a signature field on the page.", comment: "")
+            item?.toolTip = NSLocalizedString("Signature", comment: "")
             item?.titleName = NSLocalizedString("Signature", comment: "")
             item?.selectBackgroundType = .imageBox
             item?.boxImagePosition = .imageAbove