doc: Adds pinned_fcv.version as exported attribute in cluster and advanced cluster resource (#3047)

Author: oarbusi

docs/resources/advanced_cluster.md

@@ -656,7 +656,7 @@ lifecycle {
 In addition to all arguments above, the following attributes are exported:
 
 * `cluster_id` - The cluster ID.
-*  `mongo_db_version` - Version of MongoDB the cluster runs, in `major-version`.`minor-version` format.
+* `mongo_db_version` - Version of MongoDB the cluster runs, in `major-version`.`minor-version` format.
 * `id` -	The Terraform's unique identifier used internally for state management.
 * `connection_strings` - Set of connection strings that your applications use to connect to this cluster. More info in [Connection-strings](https://docs.mongodb.com/manual/reference/connection-string/). Use the parameters in this object to connect your applications to this cluster. To learn more about the formats of connection strings, see [Connection String Options](https://docs.atlas.mongodb.com/reference/faq/connection-changes/). NOTE: Atlas returns the contents of this object after the cluster is operational, not while it builds the cluster.
 
@@ -686,6 +686,7 @@ In addition to all arguments above, the following attributes are exported:
     - REPAIRING
 * `replication_specs.#.container_id` - A key-value map of the Network Peering Container ID(s) for the configuration specified in `region_configs`. The Container ID is the id of the container created when the first cluster in the region (AWS/Azure) or project (GCP) was created.  The syntax is `"providerName:regionName" = "containerId"`. Example `AWS:US_EAST_1" = "61e0797dde08fb498ca11a71`.
 * `config_server_type` Describes a sharded cluster's config server type. Valid values are `DEDICATED` and `EMBEDDED`. To learn more, see the [Sharded Cluster Config Servers documentation](https://dochub.mongodb.org/docs/manual/core/sharded-cluster-config-servers/).
+* `pinned_fcv.version` - Feature compatibility version of the cluster.
 
 
 ## Import

docs/resources/cluster.md

@@ -539,7 +539,7 @@ To learn more, see [Resource Tags](https://dochub.mongodb.org/core/add-cluster-t
 In addition to all arguments above, the following attributes are exported:
 
 * `cluster_id` - The cluster ID.
-*  `mongo_db_version` - Version of MongoDB the cluster runs, in `major-version`.`minor-version` format.
+* `mongo_db_version` - Version of MongoDB the cluster runs, in `major-version`.`minor-version` format.
 * `id` -  The Terraform's unique identifier used internally for state management.
 * `mongo_uri` - Base connection string for the cluster. Atlas only displays this field after the cluster is operational, not while it builds the cluster.
 * `mongo_uri_updated` - Lists when the connection string was last updated. The connection string changes, for example, if you change a replica set to a sharded cluster.
@@ -572,6 +572,7 @@ In addition to all arguments above, the following attributes are exported:
     - DELETING
     - DELETED
     - REPAIRING
+* `pinned_fcv.version` - Feature compatibility version of the cluster.
 
 ### Cloud Backup Policy