bug: pivot_longer() doesn't support iterable of strings

[NickCrews]

What happened?

The docstring claims this should work, but it only works with a single str or a full fledged selector.

PS I love the names pivot_wider and pivot_longer. So much better than the melt and explode. Thanks for adding this function, this would have been a doozy for me to implement myself.

What version of ibis are you using?

main

What backend(s) are you using, if any?

NA

Relevant log output

No response

Code of Conduct

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[cpcloud]

Seems easy enough to remove this part of the docstring!

[NickCrews]

But it SHOULD work with multiple columns, should the long term goal be to fix it the other direction?

[cpcloud]

It does work with multiple columns, you can use a selector!

t.pivot_longer(s.c("a", "b", "c"), ...)

[NickCrews]

Yeah, but I've managed to avoid selectors through the rest of my code, I am importing selectors just to use them in this one place.