Fix grammar issue in the doc

added "in" to fix a grammar issue

www/apps/book/app/learn/advanced-development/modules/service-constraints/page.mdx

@@ -10,7 +10,7 @@ This chapter lists constraints to keep in mind when creating a service.
 
 Medusa wraps service method executions to inject useful context or transactions. However, since Medusa can't detect whether the method is asynchronous, it always executes methods in the wrapper with the `await` keyword.
 
-For example, if you have a synchronous `getMessage` method, and you use it other resources like workflows, Medusa executes it as an async method:
+For example, if you have a synchronous `getMessage` method, and you use it in other resources like workflows, Medusa executes it as an async method:
 
 ```ts
 await helloModuleService.getMessage()