Better error message with partial AWS config and credentials

[clstokes]

Problem

If I provide partial AWS provider config (ie. only aws:region) and no credentials I get a confusing error message referring me to Terraform documentation.

p-aws-creds % pulumi config
KEY         VALUE
aws:region  us-east-1
p-aws-creds % pulumi up
Previewing update (dev)

View Live: https://app.pulumi.com/clstokes/p-aws-creds/dev/previews/33cfc380-1643-410e-960c-feabab4d43d2

     Type                 Name             Plan       Info
 +   pulumi:pulumi:Stack  p-aws-creds-dev  create
     └─ aws:s3:Bucket     my-bucket                   1 error

Diagnostics:
  aws:s3:Bucket (my-bucket):
    error: 1 error occurred:
    	* error configuring Terraform AWS Provider: no valid credential sources for Terraform AWS Provider found.

    Please see https://registry.terraform.io/providers/hashicorp/aws
    for more information about providing credentials.

    Error: NoCredentialProviders: no valid providers in chain. Deprecated.
    	For verbose messaging see aws.Config.CredentialsChainVerboseErrors


p-aws-creds %

If I provide no AWS configuration, I get a better error message:

p-aws-creds % pulumi config
KEY  VALUE
p-aws-creds % 
p-aws-creds % pulumi up
Previewing update (dev)

View Live: https://app.pulumi.com/clstokes/p-aws-creds/dev/previews/b35180b2-286b-4a0d-bf7d-aab823bd889b

     Type                 Name             Plan       Info
 +   pulumi:pulumi:Stack  p-aws-creds-dev  create
     └─ aws:s3:Bucket     my-bucket                   1 error

Diagnostics:
  aws:s3:Bucket (my-bucket):
    error: unable to discover AWS AccessKeyID and/or SecretAccessKey - see https://pulumi.io/install/aws.html for details on configuration


p-aws-creds %

Suggestions for a fix

Use the ... see https://pulumi.io/install/aws.html ... error message in the situation where the AWS provider is partially configured.

Steps to reproduce

1. pulumi new aws-typescript -y
2. pulumi up - with no AWS keys configured or available in your terminal or profile credentials file