The void scalar type should be made generic, with parameters bound to the (optional) nested field dtypes (.fields), and perhaps also its shape (.shape).

The fields type parameter should be bound to Mapping[str, tuple[dtype, int] | tuple[dtype, int, str]] | None, so that a TypedDict can be used to precisely specify the structure.

Note to self: Once implemented, be sure to also update the numpy.lib.recfunctions accordingly.