`StaticArrays.SUnitRange <: AbstractUnitRange` should be `true`?

[hyrodium]

Here's a small example.

julia> Base.OneTo <: AbstractUnitRange
true

julia> Base.UnitRange <: AbstractUnitRange
true

julia> StaticArrays.SOneTo <: AbstractUnitRange
true

julia> StaticArrays.SUnitRange <: AbstractUnitRange
false

Related comment: #855 (comment)

I think we have the following choices.

• Make abstract subtype StaticUnitRange for static range and make hierarchy SUnitRange <: StaticUnitRange <: AbstractUnitRange and SOneTo <: StaticUnitRange <: AbstractUnitRange.
• Move SOneTo <: AbstractUnitRange to SOneTo <: StaticArray.

I prefer the first. Are there any thoughts on this?

[hyrodium]

x-ref: #150 (comment)