Fix the CustomEvent's makeWithOption signature.

[mvaled]

As seen in 1, the options is an object with a detail property, not the detail directly.

[TheSpyder]

I need to finish #116 so we at least know if branches compile before I merge them 😆 there's a test that now fails to compile, because it was asserting the old object style

[TheSpyder]

Published as 0.8.0 as it's a breaking change