docs: fix className typo in zero-runtime example

Author: abyss-s

apps/landing/src/app/(detail)/docs/core-concepts/zero-runtime/page.mdx

@@ -62,7 +62,7 @@ Based on the caching results in step 3, two parallel outputs are produced.
 The bundler (Vite, Rsbuild, Next.js, Webpack) emits optimized code.
 
 ```html
-<button className="btn a b c d">Click me!</button>
+<button className="btn a b c d e">Click me!</button>
 ```
 
 Inline style props are compiled into **atomic CSS classes**, achieving zero runtime.