Docs about Cloudwatch log group in "Monitoring Runtime Logging" incorrect.

In `resource-type-develop.md`, the section [Monitoring Runtime Logging for Resource Types](https://github.com/aws-cloudformation/cloudformation-cli/blob/master/doc_source/resource-type-develop.md#monitoring-runtime-logging-for-resource-types) contains incorrect information:

1. The group is not created by Cloudformation during `cfn submit`
1. The naming scheme for the log group is incorrect

I think the corrected text would state that (a) the group is created by the Cloudformation runtime when the resource is first run, and (b) the naming scheme is `my-resource-type-logs`, where `my-resource-type` is the three-part resource type name.

Also, it could be noted that each plugin has varying requirements for logging to be emitted. For example, the Go plugin requires a build argument to enable it (see https://github.com/aws-cloudformation/cloudformation-cli-go-plugin/issues/187).