fix(prerender): only try to add / after prerender:routes hook (#2348)

Co-authored-by: Pooya Parsa <pooya@pi0.io>

Author: danielroe

src/prerender.ts

@@ -37,17 +37,17 @@ export async function prerender(nitro: Nitro) {
     routes.add(route);
   }
 
-  // Crawl / at least if no routes are defined
-  if (nitro.options.prerender.crawlLinks && routes.size === 0) {
-    routes.add("/");
-  }
-
-  // Allow extending prereneder routes
+  // Allow extending prerender routes
   await nitro.hooks.callHook("prerender:routes", routes);
 
   // Skip if no prerender routes specified
   if (routes.size === 0) {
-    return;
+    // Crawl / at least if no routes are specified
+    if (nitro.options.prerender.crawlLinks) {
+      routes.add("/");
+    } else {
+      return;
+    }
   }
 
   // Build with prerender preset