fix: coding style and file format for all example.

eBook/examples/chapter_6/defer_tracing2.go

@@ -1,25 +1,25 @@
-package main
-
-import "fmt"
-
-func trace(s string) string {
-    fmt.Println("entering:", s)
-    return s
-}
-func un(s string) {
-    fmt.Println("leaving:", s)
-}
-
-func a() {
-    defer un(trace("a"))
-	fmt.Println("in a")
-}
-
-func b() {
-	 defer un(trace("b"))
-	fmt.Println("in b")
-	a()
-}
-func main() { 
-	b() 
-}
+package main
+
+import "fmt"
+
+func trace(s string) string {
+	fmt.Println("entering:", s)
+	return s
+}
+func un(s string) {
+	fmt.Println("leaving:", s)
+}
+
+func a() {
+	defer un(trace("a"))
+	fmt.Println("in a")
+}
+
+func b() {
+	defer un(trace("b"))
+	fmt.Println("in b")
+	a()
+}
+func main() {
+	b()
+}