Carousel: fix a docs error (#4032)

examples/docs/en-US/carousel.md

@@ -162,7 +162,7 @@ When a page is wide enough but has limited height, you can activate card mode fo
 ### Carousel Attributes
 | Attribute      | Description          | Type      | Accepted Values       | Default  |
 |---------- |-------------- |---------- |--------------------------------  |-------- |
-| height | height of the carousel | number | — | 300 |
+| height | height of the carousel | string | — | — |
 | initial-index | index of the initially active slide (starting from 0) | number | — | 0 |
 | trigger | how indicators are triggered | string | hover/click | hover |
 | autoplay | whether automatically loop the slides | boolean | — | true |

examples/docs/zh-CN/carousel.md

@@ -211,7 +211,7 @@
 ### Carousel Attributes
 | 参数      | 说明          | 类型      | 可选值                           | 默认值  |
 |---------- |-------------- |---------- |--------------------------------  |-------- |
-| height | 走马灯的高度 | number | — | 300 |
+| height | 走马灯的高度 | string | — | — |
 | initial-index | 初始状态激活的幻灯片的索引，从 0 开始 | number | — | 0 |
 | trigger | 指示器的触发方式 | string | click | — |
 | autoplay | 是否自动切换 | boolean | — | true |