docs: Add faq about item height (#21433)

* docs: Add faq about item height

* update

components/select/index.en-US.md

@@ -100,3 +100,13 @@ Select component to select value from options.
 ### The dropdown is closed when click `dropdownRender` area?
 
 See the [dropdownRender example](/components/select/#components-select-demo-custom-dropdown-menu).
+
+### Why sometime customize Option cause scroll break?
+
+Virtual scroll internal set item height as `32px`. You need to adjust `listItemHeight` when your option height is less and `listHeight` config list container height:
+
+```tsx
+<Select listItemHeight={10} listHeight={250} />
+```
+
+Note: `listItemHeight` and `listHeight` are internal props. Please only modify when necessary.

components/select/index.zh-CN.md

@@ -103,3 +103,13 @@ title: Select
 ### 点击 `dropdownRender` 里的内容浮层关闭怎么办？
 
 看下 [dropdownRender 例子](/components/select-cn/#components-select-demo-custom-dropdown-menu) 里的说明。
+
+### 自定义 Option 样式导致滚动异常怎么办？
+
+这是由于虚拟滚动默认选项高度为 `32px`，如果你的选项高度小于该值则需要通过 `listItemHeight` 属性调整，而 `listHeight` 用于设置滚动容器高度：
+
+```tsx
+<Select listItemHeight={10} listHeight={250} />
+```
+
+注意：`listItemHeight` 和 `listHeight` 为内部属性，如无必要，请勿修改该值。

components/tree-select/index.en-US.md

@@ -81,3 +81,7 @@ Tree selection control.
 ### How to get parent node in onChange?
 
 We don't provide this since performance consideration. You can get by this way: <https://codesandbox.io/s/wk080nn81k>
+
+### Why sometime customize Option cause scroll break?
+
+You can ref Select [FAQ](/components/select).

components/tree-select/index.zh-CN.md

@@ -82,3 +82,7 @@ title: TreeSelect
 ### onChange 时如何获得父节点信息？
 
 从性能角度考虑，我们默认不透出父节点信息。你可以这样获得：<https://codesandbox.io/s/wk080nn81k>
+
+### 自定义 Option 样式导致滚动异常怎么办？
+
+请参考 Select 的 [FAQ](/components/select)。