[Web Bug] - AWS Quickstart: Provide basic 'credentials' debugging help

Nice quickstart overall.
But I was getting no S3 bucket created (AWS credentials errors due to a syntax error in my credentials.txt file).

Whilst this was my error, I think it would be useful to give a little help.

When attempting to create the S3 bucket, check for the creation of the bucket by
- aws s3 ls --region us-east-2 # specifying the appropriate region

Check for any events associated with the mirror resource:
- kubectl describe -n crossplane-system bucket

So finally I realised that there must be something wrong with my credentials.txt file itself.

I removed some empty lines, but I think it was the single quotes around the actual key which caused problems initially.
Once I made these changes and recreated the secret, I created my first crossplane resource

URL: https://docs.crossplane.io/latest/getting-started/provider-aws/