DOC: Freeze old whatsnew notes?

[TomAugspurger]

Currently on master, we have a new failure from the 0.10.0.txt whatsnew due to the line_width option being removed.

Rather than continuing to fix these old examples due to backwards comparability breaks in pandas, could we convert the old ..ipython:: python blocks to regular .. code-block:: python examples so they aren't run anymore? Ideally we could write a script that runs them one last time, captures the output, and updates the .rst. Anyone have interest in seeing if that's possible?

[jorisvandenbossche]

Yes! And there is already an issue for that: #6856

I at some point looked into a kind of 'text' sphinx builder that would output what we want, but never really figured it out. I think it should be somehow possible (eg numpydoc also emits the intermediate generated source code that is never saved in a file to build the actual docstring page when using very verbose mode)

[jorisvandenbossche]

Closing in favor of #6856