Apply suggestions from code review

Co-authored-by: Arsh <69170106+lilnasy@users.noreply.github.com>

packages/astro/src/vite-plugin-astro-server/response.ts

@@ -33,6 +33,7 @@ export async function default404Page(
 		pathname,
 	}), { status: 404, headers: { 'Content-Type': 'text/html; charset=utf-8' } });
 }
+// mark the function as an AstroComponentFactory for the rendering internals
 default404Page.isAstroComponentFactory = true;
 
 export async function handle500Response(