API: Index.intersection sort keyword default different from other set methods

[jbrockmendel]

Index.intersection's sort keyword defaults to False, while others default to None. If there isn't a compelling reason for this difference, we should make these match.

[jbrockmendel]

Looks like this was done intentionally in #25063. @jorisvandenbossche I see in the whatsnew note there an explicit discussion of the default being different, but not a "why". Do you remember the reason for that? This issue might be as easy as a comment

[jbrockmendel]

Changing the default breaks three tests: test_intersection_nosort, test_intersect_with_duplicates, test_concat_inner_sort.

[lukemanley]

@jbrockmendel - I think you might have intended for this issue to be about Index.intersection rather than Index.difference?

[jbrockmendel]

Yep, thanks. Updated the OP and title.