fix: delete nonexistent output (#617)

Author: ChuanfengZhang

src/guide/reactivity.md

@@ -80,7 +80,7 @@ const dinner = {
 
 const handler = {
   get(target, prop) {
-    console.log(‘intercepted!’)
+    console.log('intercepted!')
     return target[prop]
   }
 }
@@ -110,7 +110,6 @@ const handler = {
 const proxy = new Proxy(dinner, handler)
 console.log(proxy.meal)
 
-// intercepted!
 // tacos
 ```
 
@@ -131,7 +130,6 @@ const handler = {
 const proxy = new Proxy(dinner, handler)
 console.log(proxy.meal)
 
-// intercepted!
 // tacos
 ```
 
@@ -156,7 +154,6 @@ const handler = {
 const proxy = new Proxy(dinner, handler)
 console.log(proxy.meal)
 
-// intercepted!
 // tacos
 ```