Revert "docs: update moment locale usage"

This reverts commit 89228118af.

The original purpose to import locale from src is that some projects
adding `jsnext:main` to the `resolve.mainFields` config of webpack which leads
webpack load moment from `src/moment.js`. But import from `locale`
should works for most projects.

components/date-picker/index.en-US.md

@@ -36,8 +36,7 @@ import locale from 'antd/lib/date-picker/locale/zh_CN';
 ```jsx
 // The default locale is en-US, if you want to use other locale, just set locale in entry file globaly.
 import moment from 'moment';
-import 'moment/src/locale/zh-cn';
-// import 'moment/locale/zh-cn'; if you are using webpack 1
+import 'moment/locale/zh-cn';
 
 <DatePicker defaultValue={moment('2015-01-01', 'YYYY-MM-DD')} />
 ```

components/date-picker/index.zh-CN.md

@@ -37,8 +37,7 @@ import locale from 'antd/lib/date-picker/locale/zh_CN';
 ```jsx
 // 默认语言为 en-US，如果你需要设置其他语言，推荐在入口文件全局设置 locale
 import moment from 'moment';
-import 'moment/src/locale/zh-cn';
-// import 'moment/locale/zh-cn'; if you are using webpack 1
+mport 'moment/locale/zh-cn';
 
 <DatePicker defaultValue={moment('2015-01-01', 'YYYY-MM-DD')} />
 ```

components/locale-provider/index.en-US.md

@@ -14,8 +14,7 @@ title: LocaleProvider
 ```jsx
 import { LocaleProvider } from 'antd';
 import fr_FR from 'antd/lib/locale-provider/fr_FR';
-import 'moment/src/locale/fr';
-// import 'moment/locale/fr'; if you are using webpack 1
+import 'moment/locale/fr';
 
 ...
 

components/locale-provider/index.zh-CN.md

@@ -16,8 +16,6 @@ LocaleProvider 使用 React 的 [context](https://facebook.github.io/react/docs/
 import { LocaleProvider } from 'antd';
 import zh_CN from 'antd/lib/locale-provider/zh_CN';
 import 'moment/locale/zh-cn';
-// import 'moment/locale/zh-cn'; if you are using webpack 1
-
 ...
 
 return <LocaleProvider locale={zh_CN}><App /></LocaleProvider>;