QmlDesigner Binding Editor UX improvement

Binding Editor now shows which property type it expects.
Binding Editor now works with alias and unknown types.

Change-Id: I23d0bed3db5126de5107cf2f1f6b46485b89e1ea
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/components/bindingeditor/bindingeditordialog.cpp

@@ -45,7 +45,7 @@ BindingEditorDialog::BindingEditorDialog(QWidget *parent)
     : QDialog(parent)
 {
     setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
-    setWindowTitle(tr("Binding Editor"));
+    setWindowTitle(defaultTitle());
     setModal(false);
 
     setupJSEditor();
@@ -153,6 +153,11 @@ void BindingEditorDialog::unregisterAutoCompletion()
         m_editorWidget->unregisterAutoCompletion();
 }
 
+QString BindingEditorDialog::defaultTitle() const
+{
+    return titleString;
+}
+
 void BindingEditorDialog::setupJSEditor()
 {
     static BindingEditorFactory f;