Snapshot filename only uses `previewDisplayName`

[markst]

As mentioned previously #15
We use a group to render different dynamic type sizes with UIElementPreview.

It appears that the latest version of Prefire 3.6.0 outputs each snapshot tests with just the name of the view within the group and does not include the preview name itself.

This means my output snapshots are replaced:

[markst]

If I omit previewDisplayName from all my items in the group, I do get unique outputs.

But I'm just trying to investigate whether I'm better off passing the preview name to my UIElementPreview so it gets assigned to the previewDisplayName.

Prepended the name to each:

            ForEach(localizations, id: \.identifier) { locale in
                self.viewToPreview()
                    .previewLayout(.sizeThatFits)
                    .environment(\.locale, locale)
                    .previewDisplayName(".\(previewName) \(Locale.current.localizedString(forIdentifier: locale.identifier) ?? locale.identifier)")
            }