[directory-upload] Specify what HTMLInputElement::getFilesAndDirectories returns when the input type is not 'file' (#13)

Right now the text says about HTMLInputElement::getFilesAndDirectories 'If the input type is not "file", nothing occurs.' What does that mean? Does that mean that it doesn't return anything? Or that a Promise is returned but doesn't resolve? I'd suggest that it should probably throw.

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Reply to this email directly or view it on GitHub:
https://github.com/WICG/directory-upload/issues/13