Final implementation of the MenuElementsBuilder result builder

MenuElementsBuilder.swift

@resultBuilder
enum MenuElementsBuilder {

    static func buildBlock(_ elements: [UIMenuElement]...) -> [UIMenuElement] {
        return elements.flatMap { $0 }
    }

    static func buildExpression(_ element: UIMenuElement) -> [UIMenuElement] {
        return [element]
    }

    // MARK: - Conditionals

    static func buildOptional(_ component: [UIMenuElement]?) -> [UIMenuElement] {
        return component ?? []
    }

    static func buildEither(first elements: [UIMenuElement]) -> [UIMenuElement] {
        return elements
    }

    static func buildEither(second elements: [UIMenuElement]) -> [UIMenuElement] {
        return elements
    }
}