Output complex numbers using default ToString implementation

[MAS-OUD]

On page 357, by running the line WriteLine($"{c1} added to {c2} is {c3}"); I get <4; 2> added to <3; 7> is <7; 9> instead of (4, 2) added to (3, 7) is (7, 9)

[markjprice]

I initially thought this might be because number formats are culture-specific. But it seems to either be a deliberate change in behavior, or a bug, but the official documentation still shows the same formatting as I do in the book and worked in .NET 6. Regardless, I have created an item for this: https://github.com/markjprice/cs11dotnet7/blob/main/docs/errata/errata.md#page-357---working-with-complex-numbers