DOC: Add information on kind parameter to resample docstring
xref #5023

When working on another issue I couldn't find any information in the ``resample`` [docstring](https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.resample.html) on the ``kind`` parameter so I added it. There was some relevant information in the resample [section](http://pandas.pydata.org/pandas-docs/stable/timeseries.html#resampling) of the time-series documentation.
  