update book code

eBook/examples/chapter_6/blank_identifier.go

@@ -1,15 +1,14 @@
-package main
-
-import "fmt"
-
-func main() {
-        var i1 int
-        var f1 float32
-    i1, _, f1 = ThreeValues()
-    fmt.Printf("The int: %d, the float: %f \n", i1, f1)
-}
-
-func ThreeValues() (int, int, float32) {
-    return 5, 6, 7.5
-}
-
+package main
+
+import "fmt"
+
+func main() {
+	var i1 int
+	var f1 float32
+	i1, _, f1 = ThreeValues()
+	fmt.Printf("The int: %d, the float; %f\n", i1, f1)
+}
+
+func ThreeValues() (int, int, float32) {
+	return 5, 6, 7.5
+}