`FieldArray` could display better

A FieldArray displays as an array, values only. It would be great if it showed the field names too---named fields are presumably the reason to use a FieldArray in the first place.

julia> using StaticArrays

julia> Base.@kwdef struct Foo <: FieldVector{2,Float64}
           bar::Float64
           baz::Float64
       end
Foo

julia> Foo(bar=3.0, baz=5.0)
2-element Foo with indices SOneTo(2):
 3.0
 5.0

Compare LabelledArrays.jl:

julia> using LabelledArrays

julia> SLVector(bar=3.0, baz=5.0)
2-element SLArray{Tuple{2}, Float64, 1, 2, (:bar, :baz)} with indices SOneTo(2):
 :bar => 3.0
 :baz => 5.0

Locate the FieldArray display implementation and inspect how field names are represented. Compare its output with the LabelledArrays example; done means named fields such as bar and baz appear alongside their values, with coverage for the revised display behavior.