[Second review] SE-0516: `Iterable`

[grynspan (Jonathan Grynspan)]

@xwu

Fundamentally, we need a distinct name for the associated type and its corresponding protocol. It would not make it better if there were some last-ditch disambiguation syntax. We would never want to assign the same name to two distinct things that we can readily anticipate will clash like this.

Amusingly, one thread over: [Pitch] Associated Type Disambiguation