Reseeding Xoroshiro128Plus not equivalent to creating a new one

MWE (using RandomNumbers 1.6.0)

```julia
julia> using RandomNumbers

julia> seed = 12
12

julia> rng = Xorshifts.Xoroshiro128Plus(12)
RandomNumbers.Xorshifts.Xoroshiro128Plus(0x591545ee404ceb86, 0xe9c6c533699b4284)

julia> Random.seed!(rng, 12)
RandomNumbers.Xorshifts.Xoroshiro128Plus(0x018c018c0000000c, 0x8180018000003001)
```

So, I may be misunderstanding what should happen here, but from the `Random.seed!` doc string I would have expected the two objects to be the same.