Merge pull request #69 from jvincent-mongodb/DOCSP-45549

DOCSP-45549 -- Include note re GCP region names

Author: jvincent-mongodb

source/overview/supported-regions.txt

@@ -53,3 +53,12 @@ Assured Workloads is a |gcp| product that allows customers to configure sensitiv
 
 You can deploy an |cloudgov-short| cluster in GCP with Assured Workloads in all standard US regions.
 For an updated list of supported regions, see `Assured Workloads locations <https://cloud.google.com/assured-workloads/docs/locations#us_regions>`__.
+
+.. note:: 
+
+   When passing a |gcp| region name to the |service| API, as you would with 
+   Terraform for example, you must include the suffix ``_AW`` with the region name. 
+
+   For example, to pass the |gcp| region ``us-east-1`` to the |service| API, you 
+   need to pass it as ``US_EAST_1_AW``. 
+