docs: add vale rule for Next.js Starter Storefront (#12517)

www/vale/styles/docs/Tooling.yml

@@ -17,6 +17,9 @@ swap:
   "infrastructure module[s]?": "Infrastructure Module"
   "Commerce module[s]?": "Commerce Module"
   "commerce module[s]?": "Commerce Module"
+  "Next.js starter storefront": "Next.js Starter Storefront"
+  "Next.js storefront": "Next.js Starter Storefront"
+  "Next.js Storefront": "Next.js Starter Storefront"
 exceptions:
   - 'storefront framework'
   - 'Storefront Framework'