ch8: fix code format

ch8/ch8-10.md

@@ -1,24 +1,25 @@
 ## 8.10. 示例: 聊天服務
 
 我們用一個聊天服務器來終結本章節的內容，這個程序可以讓一些用戶通過服務器向其它所有用戶廣播文本消息。這個程序中有四種goroutine。main和broadcaster各自是一個goroutine實例，每一個客戶端的連接都會有一個handleConn和clientWriter的goroutine。broadcaster是select用法的不錯的樣例，因爲它需要處理三種不同類型的消息。
+
 下面演示的main goroutine的工作，是listen和accept(譯註：網絡編程里的概念)從客戶端過來的連接。對每一個連接，程序都會建立一個新的handleConn的goroutine，就像我們在本章開頭的併發的echo服務器里所做的那樣。
 
+<u><i>gopl.io/ch8/chat</i></u>
 ```go
-gopl.io/ch8/chat
 func main() {
-    listener, err := net.Listen("tcp", "localhost:8000")
-    if err != nil {
-        log.Fatal(err)
-    }
-    go broadcaster()
-    for {
-        conn, err := listener.Accept()
-        if err != nil {
-            log.Print(err)
-            continue
-        }
-        go handleConn(conn)
-    }
+	listener, err := net.Listen("tcp", "localhost:8000")
+	if err != nil {
+		log.Fatal(err)
+	}
+	go broadcaster()
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			log.Print(err)
+			continue
+		}
+		go handleConn(conn)
+	}
 }
 ```
 
@@ -28,29 +29,29 @@ func main() {
 type client chan<- string // an outgoing message channel
 
 var (
-    entering = make(chan client)
-    leaving  = make(chan client)
-    messages = make(chan string) // all incoming client messages
+	entering = make(chan client)
+	leaving  = make(chan client)
+	messages = make(chan string) // all incoming client messages
 )
 
 func broadcaster() {
-    clients := make(map[client]bool) // all connected clients
-    for {
-        select {
-        case msg := <-messages:
-            // Broadcast incoming message to all
-            // clients' outgoing message channels.
-            for cli := range clients {
-                cli <- msg
-            }
-        case cli := <-entering:
-            clients[cli] = true
+	clients := make(map[client]bool) // all connected clients
+	for {
+		select {
+		case msg := <-messages:
+			// Broadcast incoming message to all
+			// clients' outgoing message channels.
+			for cli := range clients {
+				cli <- msg
+			}
+		case cli := <-entering:
+			clients[cli] = true
 
-        case cli := <-leaving:
-            delete(clients, cli)
-            close(cli)
-        }
-    }
+		case cli := <-leaving:
+			delete(clients, cli)
+			close(cli)
+		}
+	}
 }
 ```
 
@@ -60,29 +61,29 @@ broadcaster監聽來自全局的entering和leaving的channel來獲知客戶端
 
 ```go
 func handleConn(conn net.Conn) {
-    ch := make(chan string) // outgoing client messages
-    go clientWriter(conn, ch)
+	ch := make(chan string) // outgoing client messages
+	go clientWriter(conn, ch)
 
-    who := conn.RemoteAddr().String()
-    ch <- "You are " + who
-    messages <- who + " has arrived"
-    entering <- ch
+	who := conn.RemoteAddr().String()
+	ch <- "You are " + who
+	messages <- who + " has arrived"
+	entering <- ch
 
-    input := bufio.NewScanner(conn)
-    for input.Scan() {
-        messages <- who + ": " + input.Text()
-    }
-    // NOTE: ignoring potential errors from input.Err()
+	input := bufio.NewScanner(conn)
+	for input.Scan() {
+		messages <- who + ": " + input.Text()
+	}
+	// NOTE: ignoring potential errors from input.Err()
 
-    leaving <- ch
-    messages <- who + " has left"
-    conn.Close()
+	leaving <- ch
+	messages <- who + " has left"
+	conn.Close()
 }
 
 func clientWriter(conn net.Conn, ch <-chan string) {
-    for msg := range ch {
-    fmt.Fprintln(conn, msg) // NOTE: ignoring network errors
-    }
+	for msg := range ch {
+		fmt.Fprintln(conn, msg) // NOTE: ignoring network errors
+	}
 }
 ```