DensityMatrixSimulator().simulate() return value type annotation

[mpharrigan]

Should be DensityMatrixTrialResult. Due to inheritance, it is SimulationTrialResult leading to problems if you actually try to use it

#2308 (comment)

[Ashalynd]

Shouldn't there be some consistency? E.g. all simulate() methods should return SimulationTrialResult which then can be cast to the corresponding type. (Though it seems odd too)

[daxfohl]

@balopat This has been fixed for a while and can be closed.

[mpharrigan]

Fixed by #3818