RangeEdit.__init__ should accept a range object, and SliceEdit a slice

[tlambert03]

The init of RangeEdit is

    def __init__(
        self,
        start: int = 0,
        stop: int = 10,
        step: int = 1,
        min: int | tuple[int, int, int] | None = None,
        max: int | tuple[int, int, int] | None = None,
        **kwargs,
    ):

but it should accept an instance of range, just as the value setter does.

Same thing for SliceEdit