Low-CPU Cluster Tier Doc Update

Author: Zuhairahmed

website/docs/r/advanced_cluster.html.markdown

@@ -26,6 +26,8 @@ More information on considerations for using advanced clusters please see [Consi
 
 -> **NOTE:** To enable Cluster Extended Storage Sizes use the `is_extended_storage_sizes_enabled` parameter in the [mongodbatlas_project resource](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/project).
 
+-> **NOTE:** The Low-CPU instance clusters are prefixed with `R`, i.e. `R40`. For complete list of Low-CPU instance clusters see Cluster Configuration Options under each Cloud Provider (https://www.mongodb.com/docs/atlas/reference/cloud-providers/).
+
 
 ## Example Usage
 

website/docs/r/cluster.html.markdown

@@ -18,6 +18,7 @@ description: |-
 
 -> **NOTE:** If Backup Compliance Policy is enabled for the project for which this backup schedule is defined, you cannot modify the backup schedule for an individual cluster below the minimum requirements set in the Backup Compliance Policy.  See [Backup Compliance Policy Prohibited Actions and Considerations](https://www.mongodb.com/docs/atlas/backup/cloud-backup/backup-compliance-policy/#configure-a-backup-compliance-policy).
 
+-> **NOTE:** The Low-CPU instance clusters are prefixed with `R`, i.e. `R40`. For complete list of Low-CPU instance clusters see Cluster Configuration Options under each Cloud Provider (https://www.mongodb.com/docs/atlas/reference/cloud-providers/).
 
 ~> **IMPORTANT:**
 <br> &#8226; New Users: If you are not already using `mongodbatlas_cluster` for your deployment we recommend starting with the [`mongodbatlas_advanced_cluster`](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/advanced_cluster).  `mongodbatlas_advanced_cluster` has all the same functionality as `mongodbatlas_cluster` but also supports multi-cloud clusters.