Make Loggable metaclass handle empty docstrings appropriately
Make Loggable metaclass handle empty docstrings appropriately

Empty docstrings in loggable properties or are documentation errors, but
adding the automatic documentation from Loggable just worsens the issue
by creating ill-formed and incorrect documentation as the automatic
documentation gets looked at as a type.

joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue