【fix】【BOTA - 搜索列表】小窗口，搜索替换模式，输入关键词后，删除关键词，会一直loading，只能强退APP

PDF Office/PDF Master/KMClass/Left/Search/Window/KMSearchReplaceWindowController.swift

@@ -641,6 +641,12 @@ class KMSearchReplaceWindowController: KMNBaseWindowController {
     }
     
     func search(keyboard: String) {
+        if keyboard.isEmpty {
+            handdler.resultCount = 0
+            _showIndexTip()
+            return
+        }
+        
         let isCase = KMDataManager.ud_bool(forKey: KMNSearchKey.caseSensitive.botaSearch)
         let isWholeWord = KMDataManager.ud_bool(forKey: KMNSearchKey.wholeWords.botaSearch)
         let isEditing = self.handdler.pdfView?.isEditing() ?? false