Add complex number support to linalg.det

[kgryte]

This PR

• adds support for complex numbers to linalg.det.
• updates the input and output array data types to be any floating-point data type, not just real-valued floating-point data types. In certain circumstances, the determinant of a complex matrix can be real-valued; however, this is not generally true. In which case, the guidance remains that the output data type be required to have the same data type as the input array x.

[rgommers]

LGTM, thanks @kgryte