Add some comments to patch for StaticArray

Author: N5N3

src/staticarrays_support.jl

@@ -28,7 +28,10 @@ end
 StructArrays.component(s::FieldArray, i) = invoke(StructArrays.component, Tuple{Any, Any}, s, i)
 StructArrays.createinstance(T::Type{<:FieldArray}, args...) = invoke(createinstance, Tuple{Type{<:Any}, Vararg}, T, args...)
 
+# StaticArrayStyle has no similar defined.
+# Convert to `DefaultArrayStyle` to return a sized (Struct)Array.
+# TODO: return a StaticArray?
 function Base.copy(bc::Broadcasted{StructArrayStyle{StaticArrayStyle{N},N}}) where {N}
-    B = convert(Broadcasted{StructArrayStyle{Broadcast.DefaultArrayStyle{N},N}}, bc)
-    copy(B)
+    bc′ = convert(Broadcasted{StructArrayStyle{Broadcast.DefaultArrayStyle{N},N}}, bc)
+    return copy(bc′)
 end