Docspec does not parse raw docstrings

[NiklasRosenstein]

Is your feature request related to a problem? Please describe.

If a docstring uses the r modifier, docspec does not parse it.

class Foo:
  r""" Raw docstring. """

Probably applies to f and u as well.

Describe the solution you'd like

Parse the raw docstring. Ideally it would convert the string to the same value that Foo.__doc__ would have in the example above.

Describe alternatives you've considered
N/A