Delete Cloudwatch alarm incorrectly assumes JSON is being passed to it

When deleting a Cloudwatch alarm with `aws cloudwatch delete-alarms`, if the string begins with an open square bracket (`[`), the AWS CLI will assume that JSON is being passed.

Annoyingly this only applies to deleting alarms, not creating them. To resolve the issue we have had to place the string in a JSON array with a single element.

```sh
$ aws cloudwatch delete-alarms --alarm-names "[test] this is not JSON"

Expecting value: line 1 column 2 (char 1)
$ aws cloudwatch delete-alarms --alarm-names "this is not JSON"
$ aws cloudwatch delete-alarms --alarm-names '["[test] this is not JSON"]' --region eu-west-2
$
```

In my use-case, we have alarms that begin with square brackets in order to identify the relevant deployment/service.

I am not sure if this is a lack of documentation issue (as passing an array is not in the AWS CLI public documentation) or an issue with identifying if a JSON array has been passed - I'd argue both.