Complex division (0, 0) / (0, 0) should return `.infinity`

[NevinBR]

Currently, dividing Complex(0, 0) by itself returns Complex(0, 0), but it should return .infinity to represent the undefined result.

[Stephen Canon]

This should be fixed in rescaledDivide, here:

if z.isZero || !w.isFinite { return .zero }

[Wildchild9]

This issue can be closed, the bug fix has been merged.