update 18.10.md (#500)

eBook/18.10.md

@@ -4,16 +4,16 @@
 
 ```go	
 if err != nil {
-   fmt.Printf(“Program stopping with error %v”, err)
+   fmt.Printf("Program stopping with error %v", err)
    os.Exit(1)
 }
 ```
 
-或者：
+或者：
 
 ```go
 if err != nil { 
-	panic(“ERROR occurred: “ + err.Error())
+	panic("ERROR occurred: " + err.Error())
 }
 ```