Consider alternate names for "SimulatedEffect"

[avh4]

The current name "SimulatedEffect" have been confusing to some users because the simulateEffects function you provide when creating a ProgramTest doesn't actually simulate the effects at the moment that it's called -- it actually is just interpreting your Effect type into something that elm-program-test can understand. Specifically, this is very different from simulating the response to effects, like simulating HTTP responses, which seems to be what some users more naturally think of "simulating" to refer to.

My thoughts from the Slack thread:

maybe better names for things would be

• InspectableCmd instead of SimulatedEffect
• toInspectableCmd instead of simulateEffects, and the type is effect -> InspectableCmd msg