fix(css): fix css lang regex (#11237)

Author: bluwy

packages/vite/src/node/constants.ts

@@ -47,7 +47,7 @@ export const DEFAULT_CONFIG_FILES = [
 export const JS_TYPES_RE = /\.(?:j|t)sx?$|\.mjs$/
 
 export const CSS_LANGS_RE =
-  /\.(css|less|sass|scss|styl|stylus|pcss|postcss|sss)($|\\?)/
+  /\.(css|less|sass|scss|styl|stylus|pcss|postcss|sss)(?:$|\?)/
 
 export const OPTIMIZABLE_ENTRY_RE = /\.[cm]?[jt]s$/
 

packages/vite/src/node/plugins/splitVendorChunk.ts

@@ -12,7 +12,7 @@ import type { Plugin } from '../plugin'
 // copy from constants.ts
 const CSS_LANGS_RE =
   // eslint-disable-next-line regexp/no-unused-capturing-group
-  /\.(css|less|sass|scss|styl|stylus|pcss|postcss|sss)(?:$|\\?)/
+  /\.(css|less|sass|scss|styl|stylus|pcss|postcss|sss)(?:$|\?)/
 export const isCSSRequest = (request: string): boolean =>
   CSS_LANGS_RE.test(request)