docs: fix helloWorldLoader function definition (#8429)

- Make helloWorldLoader async to follow the type definition

Closes #8428

www/apps/book/app/advanced-development/modules/container/page.mdx

@@ -56,7 +56,7 @@ import {
 } from "@medusajs/modules-sdk"
 import { Logger } from "@medusajs/medusa"
 
-export default function helloWorldLoader({
+export default async function helloWorldLoader({
   container,
 }: LoaderOptions) {
   const logger: Logger = container.resolve("logger")

www/apps/book/app/advanced-development/modules/options/page.mdx

@@ -90,7 +90,7 @@ type ModuleOptions = {
   capitalize?: boolean
 }
 
-export default function helloWorldLoader({
+export default async function helloWorldLoader({
   options,
 }: LoaderOptions<ModuleOptions>) {