Make Option<T: Finalize> implement Finalize

[jrose-signal]

Ran into this recently, though admittedly I was using Finalize outside of its primary purpose of JsBox. I considered whether Result should implement Finalize as well, but decided that was a bit trickier.

Are there any tests I should add here?

[kjvalencik]

Thanks for the contribution! This code is pretty trivial and doesn't require a test. I agree that Result would be trickier because either type (or both) might be Finalize and we would end up with overlapping impl trying to handle them.

We would only be able to provide the most strict where both <T: Finalize, E: Finalize> and that doesn't seem common enough to be useful.