fix(docs): example code in toast page (#5666)

Author: takuyahara

apps/docs/content/docs/components/toast.mdx

@@ -47,7 +47,7 @@ The `ToastProvider` must be added to the application before using the `addToast`
 import {HeroUIProvider} from '@heroui/react'
 import {ToastProvider} from "@heroui/toast";
 
-export default function Providers({children}) {
+export function Providers({children}) {
   return (
     <HeroUIProvider>
       <ToastProvider />