change prompt message

shadowsocks-csharp/Data/cn.txt

@@ -42,4 +42,4 @@ Disabled=已禁用代理
 Update PAC File via gfwlist...=基于 gfwlist 更新 PAC 文件...
 Update PAC file failed=更新 PAC 文件失败
 Update PAC file succeed=更新 PAC 文件成功
-Job running...=任务正在执行中...
+Job already running...=任务已经运行...

shadowsocks-csharp/View/MenuViewController.cs

@@ -340,7 +340,7 @@ namespace Shadowsocks.View
             if (isUpdatePACFromGFWListRunning)
             {
                 _notifyIcon.BalloonTipTitle = I18N.GetString("Update PAC File via gfwlist...");
-                _notifyIcon.BalloonTipText = I18N.GetString("Job running...");
+                _notifyIcon.BalloonTipText = I18N.GetString("Job already running...");
                 _notifyIcon.BalloonTipIcon = ToolTipIcon.Info;
                 _notifyIcon.ShowBalloonTip(5000);
             }