feat(infra): match redis and postgres VPC and subnet descriptions

since the postgres and redis templates will get merged into a single
template by Copilot when the environment is deployed, we have to
ensure that the descriptions for the VPC and subnet parameters match.

Author: lalver1

infra/copilot/environments/addons/postgres.yml

@@ -14,11 +14,11 @@ Parameters:
     # Naming constraints: https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Limits.html#RDS_Limits.Constraints
   VPCID:
     Type: String
-    Description: The ID of the VPC in which to create the Aurora Serverless v2 cluster.
+    Description: The ID of the VPC for the environment.
     Default: ""
   PrivateSubnets:
     Type: String
-    Description: The IDs of the private subnets in which to create the Aurora Serverless v2 cluster.
+    Description: The IDs of the private subnets for the environment.
     Default: ""
 
 Mappings: