SE-0483: `InlineArray` Literal Syntax

[benrimmington]

From the pitch thread:

@MPLewis

Given that there are some concerns about using x as a multiplication-like operator with whitespace around it, has anyone thought instead about dropping the leading whitespace, similar to “2x {thing}” in English?

I think it would make the value sugar (future direction) more self-explanatory.

let a = [3x 4] // Obviously `[4, 4, 4]` and not `[3, 3, 3, 3]`

However, I'm not sure about using _x or (_)x for an inferred count.

I also think tuples need a similar syntax. For example, in Foundation.UUID public APIs:

typealias uuid_t = (16x UInt8)
var uuid: uuid_t = (16x 0)