fix(commands): fix an off-by-one in toggle_option

[RoloEdits]

With the off-by-one, it would work only if the first option was not the same something as what the option was currently set. Now, it properly toggles.

There is still an existing issue that this way of toggling really only toggles for two options, but more are supposed to be accepted. I would argue though that is actually what "toggle" is supposed to be, not a "cycle".

[the-mikedavis]

There is still an existing issue that this way of toggling really only toggles for two options, but more are supposed to be accepted. I would argue though that is actually what "toggle" is supposed to be, not a "cycle".

Accepting more than two options was intentional, see #4411

[RoloEdits]

I think even with that old way it wasn't sound with duplicate inputs. Is it still worth keeping that spurious behavior for the cases that it works?

[RoloEdits]

Should work the same as before. The off-by-one was calling nth(1) instead of next in the unwrap_or_else.

[RoloEdits]

Will open up a new one with this fix included in the larger changes.