Enhance error; improve comments.

Author: shepazon

swift/example_code/support/scenario/Sources/Scenario.swift

@@ -309,7 +309,7 @@ class Scenario {
                 print("*** You need a subscription to use AWS Support.")
                 return []
             } else {
-                print("*** An unanticipated error occurred getting support information: \(error.errorCode ?? "<unknown>").")
+                print("*** An unanticipated error occurred getting support information: \(error.message ?? "") (\(error.errorCode ?? "<unknown>")).")
                 return []
             }
         } catch {

swift/example_code/support/scenario/Sources/entry.swift

@@ -5,9 +5,9 @@
 // An example that shows how to use the AWS SDK for Swift to perform a series
 // of operations using AWS Support
 //
-// NOTE: You must have a business class AWS account to use AWS Support
-// features. See https://aws.amazon.com/premiumsupport/plans/.
-//
+// NOTE: You must have one of the following AWS Support plans to use the AWS
+// Support API: Business, Enterprise On-Ramp, or Enterprise. For more
+// information, see: https://aws.amazon.com/premiumsupport/plans/.
 
 import ArgumentParser
 import AWSClientRuntime