Update 06.9.md (#423)

line 23 : a gets value 2 not 3

eBook/06.9.md

@@ -20,7 +20,7 @@ func main() {
 	// make an Add2 function, give it a name p2, and call it:
 	p2 := Add2()
 	fmt.Printf("Call Add2 for 3 gives: %v\n", p2(3))
-	// make a special Adder function, a gets value 3:
+	// make a special Adder function, a gets value 2:
 	TwoAdder := Adder(2)
 	fmt.Printf("The result is: %v\n", TwoAdder(3))
 }