docs: add translation for timeline (#2190)

components/timeline/demo/basic.md

@@ -1,10 +1,18 @@
 ---
 order: 0
-title: 基本用法
+title: 
+  zh-CN: 基本用法
+  en-US: Basic
 ---
 
+## zh-CN
+
 基本的时间轴。
 
+## en-US 
+
+Basic timeline.
+
 ````jsx
 import { Timeline } from 'antd';
 

components/timeline/demo/color.md

@@ -1,10 +1,18 @@
 ---
 order: 1
-title: 圆圈颜色
+title: 
+  zh-CN: 圆圈颜色
+  en-US: Color
 ---
 
+## zh-CN
+
 圆圈颜色，绿色用于已完成、成功状态，红色表示告警或错误状态，蓝色可表示正在进行或其他默认状态。
 
+## en-US 
+
+Set the color of circles. `green` means completed or success status, `red` means warning or error, and `blue` means ongoing or other default status.
+
 ````jsx
 import { Timeline } from 'antd';
 

components/timeline/demo/custom.md

@@ -1,10 +1,18 @@
 ---
 order: 4
-title: 自定义时间轴点
+title: 
+  zh-CN: 自定义时间轴点
+  en-US: Custom
 ---
 
+## zh-CN
+
 可以设置为图标或其他自定义元素。
 
+## en-US 
+
+Set a node as an icon or other custom element.
+
 ````jsx
 import { Timeline, Icon } from 'antd';
 

components/timeline/demo/pending.md

@@ -1,10 +1,18 @@
 ---
 order: 2
-title: 最后一个
+title: 
+  zh-CN: 最后一个
+  en-US: Last node
 ---
 
+## zh-CN
+
 在最后位置添加一个幽灵节点，表示时间轴未完成，还在记录过程中。可以指定 `pending={true}` 或者 `pending={一个 React 元素}`。
 
+## en-US
+
+When the timeline is incomplete and ongoing, put a ghost node at last. set `pending={true}` or `pending={a React Element}`。
+
 ````jsx
 import { Timeline } from 'antd';
 

components/timeline/index.en-US.md

@@ -0,0 +1,40 @@
+---
+category: Components
+type: Views
+title: Timeline
+---
+
+Vertical display timeline.
+
+## When To Use
+
+- When a series of information need to be lined from top to bottom by time.
+- When need a timeline to make a visual connection.
+
+## API
+
+```jsx
+<Timeline>
+  <Timeline.Item>step1 2015-09-01</Timeline.Item>
+  <Timeline.Item>step2 2015-09-01</Timeline.Item>
+  <Timeline.Item>step3 2015-09-01</Timeline.Item>
+  <Timeline.Item>step4 2015-09-01</Timeline.Item>
+</Timeline>
+```
+
+### Timeline
+
+Timeline
+
+| Property      | Description                                     | Type       | Default |
+|----------|----------------------------------------|------------|-------|
+| pending  | to set the last ghost node's existence or its content | boolean or React.Element | false  |
+
+### Timeline.Item
+
+Node of timeline
+
+| Property      | Description                                     | Type       | Default |
+|----------|------------------------------------------|------------|-------|
+| color   | to set the circle's color to `blue, red, green` or other custom colors | string | blue  |
+| dot   | custom timeline dot | React.Element | -  |