fix(sfc/style-vars): improve ignore style variable bindings in comments (#4202)

packages/compiler-sfc/__tests__/__snapshots__/cssVars.spec.ts.snap

@@ -50,11 +50,17 @@ export default __default__"
 `;
 
 exports[`CSS vars injection codegen should ignore comments 1`] = `
-"export default {
+"import { useCssVars as _useCssVars, unref as _unref } from 'vue'
+
+export default {
   setup(__props, { expose }) {
   expose()
-const color = 'red'
-return { color }
+
+_useCssVars(_ctx => ({
+  \\"xxxxxxxx-width\\": (width)
+}))
+const color = 'red';const width = 100
+return { color, width }
 }
 
 }"