docs: number default is -1

Author: booxood

readme-cn.md

@@ -91,7 +91,7 @@ gitalk.render('gitalk-container')
 
 - **number** `Number` 
 
- Default: `null`.
+ Default: `-1`.
 
  页面的 issue ID 标识，若未定义`number`属性则会使用`id`进行定位。
 

readme-zh.md

@@ -92,7 +92,7 @@ gitalk.render('gitalk-container')
 
 - **number** `Number` 
 
- Default: `null`.
+ Default: `-1`.
 
  頁面的 issue ID，若未定義`number`屬性則會使用`id`進行定位。 
 

readme.md

@@ -94,7 +94,7 @@ gitalk.render('gitalk-container')
 
 - **number** `Number` 
 
- Default: `location.href`.
+ Default: `-1`.
 
  The issue ID of the page, if the `number` attribute is not defined, issue will be located using `id`.