message: docs: add file extension
diff: @@ -8,7 +8,7 @@ When your app grows and becomes more complex, you can use **Providers** (it's ju
  You can define a provider and add it to your module.
  -`modules/my-module/user.provider`
  +`modules/my-module/user.provider.ts`
  ```typescript
  import { Injectable } from '@graphql-modules/di';
  