Catch empty lines in docstrings

[mbeach-aws]

Describe the feature you'd like
It might be nice to catch empty-line formatting like:

Args:
   arg1: stuff
   
   arg2: stuff

when it could be

Args:
   arg1: stuff
   arg2: stuff

[krneta]

Looking through our code, it seems like there are places we actually allow this : https://github.com/aws/amazon-braket-sdk-python/blob/main/src/braket/aws/aws_quantum_task.py#L112

So I'm not sure if it should be an error or not.