Allow Quantity.__mul__ and .__truediv__ with Reals

[llucax]

From:

• Add Quantity types and update formulas to produce typed Samples #422 (comment)

@llucax

I think in general we should also provide __mul__ and __truediv__ with other: float: Power.from_watts(10) / 2 == Power.from_watts(5).

@shsms

Also from a performance point of view, this might be bad, especially if we also want to support division by multiple types, and we have to call isinstance 3 times to get to the right type. And then isinstance(v, float) will reject ints, but the typing system will accept ints, so have to have an explicit runtime type check for ints also.

@llucax

With numbers.Real we need only one:

    def __truediv__(self, other: Current | Voltage | float) -> Voltage | Current | Power:
        if isinstance(other, Current):
            return Voltage(self._base_value / other._base_value, exponent=0)
        if isinstance(other, Voltage):
            return Current(self._base_value / other._base_value, exponent=0)
        if isinstance(other, numbers.Real):  # Only 1 extra `isinstance()` for all reals (`int` and `float` and whatever user-defined type that inherits from `numbers.Real`)
            return type(self)(self._base_value / other, exponent=0)
        raise TypeError(
            f"unsupported operand type(s) for /: '{type(self)}' and '{type(other)}'"
        )

>>> import numbers
>>> isinstance(1, numbers.Real)
True
>>> isinstance(1.0, numbers.Real)
True