gh-1420: Add a note about long paths support to Windows buildbot setup

[itamaro]

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📚 Documentation preview 📚: https://cpython-devguide--1421.org.readthedocs.build/

[zware]

I'm torn on this one :). It's good information to add, but ideally our tests should handle the 'disabled' case, since it's the default.

[itamaro]

It's good information to add, but ideally our tests should handle the 'disabled' case, since it's the default.

why not both? :)

if the test suite handles the disabled case (likely by skipping some tests when long paths are disabled), then we probably want to nudge buildbot worker maintainers to enable long paths to get more comprehensive coverage.

[zware]

Fair enough.