Update 02.6.md

fix typo

Author: zddhub

zh/02.6.md

@@ -268,7 +268,7 @@ interface的变量可以持有任意实现该interface类型的对象，这给
 				} else if value, ok := element.(Person); ok {
 					fmt.Printf("list[%d] is a Person and its value is %s\n", index, value)
 				} else {
-					fmt.Println("list[%d] is of a different type", index)
+					fmt.Printf("list[%d] is of a different type\n", index)
 				}
 			}
 		}