Clarified that to send notifications to more than one Lambda function requires a single `s3_bucket_notification` element with multiple `lambda_function` configuration elements.
If multiple `s3_bucket_notification` elements, each with a single `lambda_function` element are used, one of the configurations is applied, seemingly at random.
When adding multiple notifications from one S3 bucket to one SQS queue, it wasn't immediately intuitive how to do this.
At first I created two `aws_s3_bucket_notification` configs and it seemed to work fine, however the config for one event
will overwrite the other. In order to have multiple events, you can defined the `queue` key twice, or use an array if you're
working with the JSON syntax. I tried to make this more clear in the documentation.
