docs: update inheritance.md (vuejs#1774)

xerrors · ulivz · commit 776a0ee39ec5 · 2019-08-25T15:34:41.000+08:00
diff --git a/packages/docs/docs/zh/theme/inheritance.md b/packages/docs/docs/zh/theme/inheritance.md
@@ -27,6 +27,7 @@
 假设你想创建一个继承自 VuePress 默认主题的派生主题，你只需要在你的主题配置中配置 [extend](./option-api.md#extend) 选项：
 
 ```js
+// themePath/index.js
 module.exports = {
   extend: '@vuepress/theme-default'
 }

Original file line number	Diff line number	Diff line change
`@@ -27,6 +27,7 @@`
`27`	`27`	`假设你想创建一个继承自 VuePress 默认主题的派生主题，你只需要在你的主题配置中配置 [extend](./option-api.md#extend) 选项：`
`28`	`28`
`29`	`29`	```js
	`30`	`+// themePath/index.js`
`30`	`31`	`module.exports = {`
`31`	`32`	`extend: '@vuepress/theme-default'`
`32`	`33`	`}`