docs: updates for next release (#14275)

www/apps/book/app/learn/deployment/general/page.mdx

@@ -171,7 +171,9 @@ module.exports = defineConfig({
       resolve: "@medusajs/medusa/workflow-engine-redis",
       options: {
         redis: {
-          url: process.env.REDIS_URL,
+          // Note: This was `url` before v2.12.2
+          // It's now deprecated in favor of `redisUrl`
+          redisUrl: process.env.REDIS_URL,
         },
       },
     },