feat(cli): add css.removeSourceFile config (#10750)

packages/vant-cli/docs/config.md

@@ -103,7 +103,7 @@ module.exports = {
 - Type: `string`
 - Default: `'less'`
 
-CSS preprocess Config, support `less` and `sass`. Use `less` by default.
+CSS preprocessor config, support `less` and `sass`. Use `less` by default.
 
 ```js
 module.exports = {
@@ -115,6 +115,23 @@ module.exports = {
 };
 ```
 
+### build.css.removeSourceFile
+
+- Type: `boolean`
+- Default: `'false'`
+
+Whether to remove the source style files after build.
+
+```js
+module.exports = {
+  build: {
+    css: {
+      removeSourceFile: true,
+    },
+  },
+};
+```
+
 ### build.site.publicPath
 
 - Type: `string`

packages/vant-cli/docs/config.zh-CN.md

@@ -115,6 +115,23 @@ module.exports = {
 };
 ```
 
+### build.css.removeSourceFile
+
+- Type: `boolean`
+- Default: `'false'`
+
+是否在构建后移除样式文件的源代码。
+
+```js
+module.exports = {
+  build: {
+    css: {
+      removeSourceFile: true,
+    },
+  },
+};
+```
+
 ### build.site.publicPath
 
 - Type: `string`