Fix value for not_found_handling example (cloudflare#25138)

Author: levidurfee

src/content/docs/workers/framework-guides/web-apps/react.mdx

@@ -94,7 +94,7 @@ import {
 
 ## Asset Routing
 
-If you're using React as a SPA, you will want to set `not_found_handling = "single_page_application"` in your Wrangler configuration file.
+If you're using React as a SPA, you will want to set `not_found_handling = "single-page-application"` in your Wrangler configuration file.
 
 <Render file="workers-assets-routing-summary" product="workers" />