CI: azure failing

[jreback]

https://dev.azure.com/pandas-dev/pandas/_build/results?buildId=6880

doc/source/comparison_with_sas.rst(754,-22): error F821: undefined name 'get_ipython'
Bash exited with code '1'.

[jreback]

azure seems to be failing on master, with the above. not sure where its coming from.

cc @datapythonista

[datapythonista]

Let me take a look.

[datapythonista]

Seems like a problem in the latest release of flak8-rst. It's been reported an internal error of flake8-rst as if it was in our documentation.

@FHaase should I create an issue in flake8-rst or can you take a look?

Opened #24756