Simply the combobox's internal state handling of the open-state (#926)

Author: haukesomm

headless-demo/src/jsMain/kotlin/dev/fritz2/headlessdemo/App.kt

@@ -50,6 +50,7 @@ val pages: Map<String, Page> = mapOf(
             | robust support for keyboard naigation.""".trimMargin(),
         RenderContext::comboboxDemo
     ),
+    "comboboxTestdrive" to TestDrive(RenderContext::comboboxTestdrive),
     "menu" to DemoPage(
         "Headless Menu",
         """Menus offer an easy way to build custom, accessible dropdown components with robust support for keyboard