docs: update docs

Author: haoziqaq

packages/varlet-ui/src/select/docs/en-US.md

@@ -665,3 +665,7 @@ Here are the CSS variables used by the component. Styles can be customized using
 | `--option-font-size` | `16px` |
 | `--option-selected-background` | `var(--input-decorator-focus-color)` |
 | `--option-text-color` | `#555` |
+
+#### Variant Variables
+
+For style variables related to variant, please refer to the style variables of the [Input component](#/en-US/input#yang4shi4bian4liang4).

packages/varlet-ui/src/select/docs/zh-CN.md

@@ -668,3 +668,7 @@ const keyOptions = computed(() => [
 | `--option-font-size` | `16px` |
 | `--option-selected-background` | `var(--input-decorator-focus-color)` |
 | `--option-text-color` | `#555` |
+
+#### Variant Variables
+
+外观相关的样式变量请参考 [Input 组件](#/zh-CN/input#yang4shi4bian4liang4) 的样式变量