Fix docs (#17226)
- closes #17226

Hello @RaghavBatra! Thanks for updating the PR.

 - In the file [`pandas/core/generic.py`](https://github.com/pandas-dev/pandas/blob/8646301902fed0771030178722722e017b1ef83d/pandas/core/generic.py), following are the PEP8 issues :

> [Line 4126:70](https://github.com/pandas-dev/pandas/blob/8646301902fed0771030178722722e017b1ef83d/pandas/core/generic.py#L4126): [W291](https://duckduckgo.com/?q=pep8%20W291) trailing whitespace



##### Comment last updated on August 11, 2017 at 13:07 Hours UTC @RaghavBatra : So the fix will be a little more involved than this.  If you try installing your branch, you will see that the documentation will now be incorrect for `DataFrame.replace`.  I think you might have to define `replace` in the `Series` class and add custom documentation there (unless I'm forgetting some doc-trick @jreback ?) Hey this looks like more work than I thought. Maybe later and thanks for your help!