Improve documentation
Improve documentation

Incrementally moving to numpy-style docstrings. Also, remove
redundant/wrong information. Eventually this docstring needs to be
clarified, but I think it makes more sense to revisit when we fix the
issue that blocksize has no effect.

Parsl/parsl,swift-lang/swift-e-lab,Parsl/parsl,Parsl/parsl,swift-lang/swift-e-lab,Parsl/parsl