Update frame.py
Built the example inside the docstring and removed the unnecessary inplace=true

- [x] closes #xxxx
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [x] whatsnew entry

Hello @trevorkask! Thanks for opening this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:

* In the file [`pandas/core/frame.py`](https://github.com/pandas-dev/pandas/blob/d1c8182e7430252247a7da6ff8b8c44725c55516/pandas/core/frame.py):

> [Line 6809:1](https://github.com/pandas-dev/pandas/blob/d1c8182e7430252247a7da6ff8b8c44725c55516/pandas/core/frame.py#L6809): [W293](https://duckduckgo.com/?q=pep8%20W293) blank line contains whitespace

 can u please just push to the open PE

creating new PRs just makes more work