Apply SidebarListStyle() to Mac only

In my Catalyst project I'd like to apply `SidebarListStyle()` to Mac only.

My problem is I can't build the project, even when I check for OS. Heres an example:

    struct CrossList: View {
        #if targetEnvironment(macCatalyst)
        var body: some View {
            List {
                Text("Mac Test")
            }
            .listStyle(SidebarListStyle())
        }
        #else
        var body: some View {
            List {
                Text("iOS Test")
            }
        }
        #endif
    }

This gives me the following error when building:

> 'SidebarListStyle' is unavailable in iOS