Missing formatting backtick in the documentation (#457)

Author: lescactus

website/docs/r/global_cluster_config.html.markdown

@@ -112,7 +112,7 @@ resource "mongodbatlas_global_cluster_config" "config" {
 ## Argument Reference
 
 * `project_id` - (Required) The unique ID for the project to create the database user.
-* `cluster_name - (Required) The name of the Global Cluster.
+* `cluster_name` - (Required) The name of the Global Cluster.
 *  `managed_namespaces` - (Optional) Add a managed namespaces to a Global Cluster. For more information about managed namespaces, see [Global Clusters](https://docs.atlas.mongodb.com/reference/api/global-clusters/). See [Managed Namespace](#managed-namespace) below for more details.
 *  `custom_zone_mappings` - (Optional) Each element in the list maps one ISO location code to a zone in your Global Cluster. See [Custom Zone Mapping](#custom-zone-mapping) below for more details.
 
@@ -143,4 +143,4 @@ Database users can be imported using project ID and cluster name, in the format
 $ terraform import mongodbatlas_global_cluster_config.config 1112222b3bf99403840e8934-my-cluster
 ```
 
-See detailed information for arguments and attributes: [MongoDB API Global Clusters](https://docs.atlas.mongodb.com/reference/api/global-clusters/)
+See detailed information for arguments and attributes: [MongoDB API Global Clusters](https://docs.atlas.mongodb.com/reference/api/global-clusters/)