COMPAT: Change khcomplex64/128_t typedefs
xref https://github.com/numpy/numpy/pull/24085

suggestion by @seberg 
@mroeschke 
Looks like some failures
```
FAILED pandas/tests/io/formats/test_printing.py::test_ser_df_with_complex_nans[True-data6-output6] - AssertionError
FAILED pandas/tests/io/formats/test_printing.py::test_ser_df_with_complex_nans[False-data6-output6] - AssertionError
``` Can't reproduce this locally, but it seems that `float real` of `complex(1.2, nan)` is returning NaN instead of 1.2. Any ideas @WillAyd  I think it might be a Python 3.12 issue. The regular numpy dev build doesn't fail. > I think it might be a Python 3.12 issue. The regular numpy dev build doesn't fail.

I think numpy dev has cached dependencies so maybe the changes haven't caught up Looks like this change subtly changed how `maybe_convert_objects` infers complex scalars, but given that the failing test is a net new fix in 2.1 and the failure is an edge case with nan, I think the status quo is better that the behavior in 2.0 so merging as is.