[APIM] Workspace gateway regions

Author: dlepow

articles/api-management/workspaces-overview.md

@@ -88,7 +88,7 @@ Manage gateway capacity by manually adding or removing scale units, similar to t
 
 ### Regional availability
 
-Workspace gateways need to be in the same Azure region and subscription as the API Management service. 
+Workspace gateways are currently available in the following regions:
 
 > [!NOTE]
 > These regions are a subset of those where API Management is available.
@@ -107,6 +107,7 @@ Workspace gateways need to be in the same Azure region and subscription as the A
 ### Gateway constraints
 The following constraints currently apply to workspace gateways:
 
+* A workspace gateway needs to be in the same region as the API Management instance's primary Azure region and in the same subscription. 
 * A gateway can be associated only with one workspace
 * A workspace can't be associated with a self-hosted gateway
 * Workspace gateways don't support inbound private endpoints