This PR changes the Control parameter nMCMC to an int. It is currently a float greater than or equal to zero, but if you set it to a non-integer value then the process hangs (because it is supposed to be an integer). It is a float in the C++ code, and pybind11 automatically converts the integer to a float when the C++ Controls object is made: to test this you can try

from RATapi.inputs import make_input
_, _, _, _, cpp_controls = make_input(problem, RAT.Controls(procedure="ns"))
print(cpp_controls.nMCMC)

and see that it prints 0.0.

Also fixes ruff linting as the latest ruff update made it lint jupyter notebooks by default.