docs: correct possible size size in component Select (#7991)

Author: Attacktive

components/select/index.en-US.md

@@ -63,7 +63,7 @@ Select component to select value from options.
 | searchValue | The current input "search" text | string | - |  |
 | showArrow | Whether to show the drop-down arrow | boolean | single:true, multiple:false |  |
 | showSearch | Whether select is searchable | boolean | single:false, multiple:true |  |
-| size | Size of Select input. `default` `large` `small` | string | default |  |
+| size | Size of Select input. `middle` `large` `small` | string | middle |  |
 | status | Set validation status | 'error' \| 'warning' | - | 3.3.0 |
 | suffixIcon | The custom suffix icon | VNode \| slot | - |  |
 | tagRender | Customize tag render, only applies when `mode` is set to `multiple` or `tags` | slot \| (props) => any | - |  |

components/select/index.zh-CN.md

@@ -63,7 +63,7 @@ coverDark: https://mdn.alipayobjects.com/huamei_7uahnr/afts/img/A*5oPiTqPxGAUAAA
 | searchValue | 控制搜索文本 | string | - |  |
 | showArrow | 是否显示下拉小箭头 | boolean | 单选为 true,多选为 false |  |
 | showSearch | 配置是否可搜索 | boolean | 单选为 false,多选为 true |  |
-| size | 选择框大小，可选 `large` `small` | string | default |  |
+| size | 选择框大小，可选 `middle` `large` `small` | string | middle |  |
 | status | 设置校验状态 | 'error' \| 'warning' | - | 3.3.0 |
 | suffixIcon | 自定义的选择框后缀图标 | VNode \| slot | - |  |
 | tagRender | 自定义 tag 内容 render，仅在 `mode` 为 `multiple` 或 `tags` 时生效 | slot \| (props) => any | - | 3.0 |