Before this change, operations.moveOrCopyFile had a special section to detect
and handle changing case of a file on a case insensitive remote, but
operations.Move did not. This caused operations.Move to fail for certain
backends that are incapable of renaming a file in-place to an equal-folding name.
(Not all case-insensitive backends have this limitation -- for example, Dropbox
does but macOS local does not.)
After this change, the special two-part-move section from
operations.moveOrCopyFile is factored out to its own function,
moveCaseInsensitive, which is then called from both operations.moveOrCopyFile
and operations.Move.