匿名字段例子代码中fmt.Println参数修改

增加逗号，使编译通过

Author: wisape

2.4.md

@@ -191,9 +191,9 @@ Go里面很简单的解决了这个问题，最外层的优先访问，也就是
 
 	func main() {
 	    Bob := Employee{Human{"Bob", 34, "777-444-XXXX"}, "Designer", "333-222"}
-	    fmt.Println("Bob's work phone is: " Bob.phone)
+	    fmt.Println("Bob's work phone is:", Bob.phone)
 	    //如果我们要访问Human的phone字段
-	    fmt.Println("Bob's personal phone is: " Bob.Human.phone)
+	    fmt.Println("Bob's personal phone is:", Bob.Human.phone)
 	}