How to handle NSSearchToolbarItem in macOS 11

Issue #758

extension NSToolbarItem.Identifier {
    static let searchItem: NSToolbarItem.Identifier = NSToolbarItem.Identifier("SearchItem")
}

let searchItem = NSSearchToolbarItem(itemIdentifier: .searchItem)

extension AppDelegate: NSToolbarDelegate {
    func toolbar(
        _ toolbar: NSToolbar,
        itemForItemIdentifier itemIdentifier: NSToolbarItem.Identifier,
        willBeInsertedIntoToolbar flag: Bool
    ) -> NSToolbarItem? {
        switch itemIdentifier {
        case .searchItem:
            searchItem.searchField.delegate = self
            return searchItem
        }
}


extension AppDelegate: NSSearchFieldDelegate {
    func control(
        _ control: NSControl,
        textView: NSTextView,
        doCommandBy commandSelector: Selector
    ) -> Bool {
        if (commandSelector == #selector(NSResponder.insertNewline(_:))) {
            print("enter")
            return true
        }

        return false
    }
}