Arb.choice should take Arb instances and not combine edgecases into arb.values().

[jaymoid]

Currently Arb.choice takes Gen instances as parameters and combines the edgecases and the arb values. Such that you get the edgecases first when you call .values() on the resulting Arb instance. In addition the edgecases in the passed in Arbs are not available via the edgecases() function on the resulting Arb, instead you get an empty list.

As this might might not be expected, and invoking choice on an Exhaustive is counter intuitive, after discussing with @sksamuel in slack, it's been suggested that we:

• Change Arb.choice to accept vararg Arb<A>
• Combine the edgecases from the provided Arbs, and make available via resulting Arb.edgecases
• Expect values from the provided Arb instances to be available via the resulting .values()
• deprecate the existing one and replace it with the below
• Use @JvmName to keep the same function name with the varargs
  Something like:

fun <A> Arb.Companion.choice(vararg arbs: Arb<A>): Arb<A> = arb (arbs.flatMap(Arb<A>::edgecases)){ rs ->
    val iters = arbs.map { it.values(rs).iterator() }
...

I'm happy to have a go at this.