fix typoes in the code comments

Author: ksmin23

cdk_stacks/vpc.py

@@ -15,7 +15,7 @@ class VpcStack(Stack):
   def __init__(self, scope: Construct, construct_id: str, **kwargs) -> None:
     super().__init__(scope, construct_id, **kwargs)
 
-    #XXX: For createing Amazon MWAA in the existing VPC,
+    #XXX: For creating the CDK Stacks in the existing VPC,
     # remove comments from the below codes and
     # comments out vpc = aws_ec2.Vpc(..) codes,
     # then pass -c vpc_name=your-existing-vpc to cdk command