update doc

site/src/site/sphinx/en/quick-start.md

@@ -1,7 +1,7 @@
 Quick Start
 ===========
 
-## 1. Start Demo Application
+## 1. Start math-game
 
 ```bash
 curl -O https://arthas.aliyun.com/math-game.jar
@@ -35,7 +35,7 @@ $ $ java -jar arthas-boot.jar
   [2]: 71560 math-game.jar
 ```
 
-The 'Demo' process is the second as shown above, press '2' then 'Enter'. Arthas will attach to the target process, and start to output:
+The `math-game` process is the second as shown above, press '2' then 'Enter'. Arthas will attach to the target process, and start to output:
 
 ```bash
 [INFO] Try to attach process 71560

site/src/site/sphinx/quick-start.md

@@ -1,7 +1,7 @@
 快速入门
 ===
 
-## 1. 启动Demo
+## 1. 启动math-game
 
 ```bash
 curl -O https://arthas.aliyun.com/math-game.jar
@@ -36,7 +36,7 @@ $ $ java -jar arthas-boot.jar
   [2]: 71560 math-game.jar
 ```
 
-Demo进程是第2个，则输入2，再输入`回车/enter`。Arthas会attach到目标进程上，并输出日志：
+`math-game`进程是第2个，则输入2，再输入`回车/enter`。Arthas会attach到目标进程上，并输出日志：
 
 ```bash
 [INFO] Try to attach process 71560

tutorials/katacoda/arthas-advanced-cn/index.json

@@ -4,7 +4,7 @@
   "details": {
     "steps": [
       {
-        "title": "启动demo",
+        "title": "启动math-game",
         "text": "start-demo.md"
       },
       {

tutorials/katacoda/command-classloader-cn/index.json

@@ -6,7 +6,7 @@
   "details": {
     "steps": [
       {
-        "title": "启动demo",
+        "title": "启动math-game",
         "text": "start-demo.md"
       },
       {

tutorials/katacoda/command-logger-cn/index.json

@@ -6,7 +6,7 @@
   "details": {
     "steps": [
       {
-        "title": "启动demo",
+        "title": "启动math-game",
         "text": "start-demo.md"
       },
       {

tutorials/katacoda/command-mc-redefine-cn/index.json

@@ -6,7 +6,7 @@
   "details": {
     "steps": [
       {
-        "title": "启动demo",
+        "title": "启动math-game",
         "text": "start-demo.md"
       },
       {

tutorials/katacoda/command-mc-retransform-cn/index.json

@@ -6,7 +6,7 @@
   "details": {
     "steps": [
       {
-        "title": "启动demo",
+        "title": "启动math-game",
         "text": "start-demo.md"
       },
       {

tutorials/katacoda/command-ognl-cn/index.json

@@ -6,7 +6,7 @@
   "details": {
     "steps": [
       {
-        "title": "启动demo",
+        "title": "启动math-game",
         "text": "start-demo.md"
       },
       {