Add a note to change the tfc_hostname variable (#1068)

Author: rkoron007

content/terraform-docs-common/docs/cloud-docs/integrations/aws-service-catalog/index.mdx

@@ -27,6 +27,16 @@ By combining HCP Terraform with AWS Service Catalog, we’re combining a self-se
 
 ## Installation & Configuration
 
+<!-- BEGIN: TFC:only name:hcp-eu -->
+
+<Note>
+
+To use the AWS service catalog integration with an HCP Europe organization, set the example [`tfc_hostname` variable](https://github.com/hashicorp/aws-service-catalog-engine-for-tfc/blob/main/variables.tf#L15-L19) to `app.eu.terraform.io` in your configuration.
+
+</Note>
+
+<!-- END: TFC:only name:hcp-eu -->
+
 To start using this integration, you'll need to install the [AWS Service Catalog Engine for Terraform Cloud](https://github.com/hashicorp/aws-service-catalog-engine-for-tfc) provided by HashiCorp on GitHub by following the [setup instructions](https://github.com/hashicorp/aws-service-catalog-engine-for-tfc#getting-started) provided in the README. If you run into any setup troubles along the way, the README also includes [troubleshooting steps](https://github.com/hashicorp/aws-service-catalog-engine-for-tfc#troubleshooting) that should help resolve common issues that you may encounter.
 
 With the engine installed, the necessary code and infrastructure to integrate the HCP Terraform engine with AWS Service Catalog will automatically be configured. The setup can be completed in just a few minutes, and it only needs to be done once. Once the setup is complete, you can immediately start using AWS Service Catalog to develop and manage AWS Service Catalog products, and make them accessible to your end users across all your accounts.