message: docs(Checkbox): add direction usage document
diff: @@ -93,7 +93,6 @@ When Checkboxes are inside a CheckboxGroup, the checked checkboxes's name is an
  <van-checkbox-group v-model="result">
  <van-checkbox name="a">Checkbox a</van-checkbox>
  <van-checkbox name="b">Checkbox b</van-checkbox>
  - <van-checkbox name="c">Checkbox c</van-checkbox>
  </van-checkbox-group>
  ```
  @@ -107,6 +106,25 @@ export default {
  };
  ```
  +### Horizontal
  +
  +```html
  +<van-checkbox-group v-model="result" direction="horizontal">
  + <van-checkbox name="a">Checkbox a</van-checkbox>
  + <van-checkbox name="b">Checkbox b</van-checkbox>
  +</van-checkbox-group>
  +```
  +
  +```js
  +export default {
  + data() {
  + return {
  + result: []
  + };
  + }
  +};
  +```
  +
  ### Maximum amount of checked options
  ```html
  