Defines UxmlTraits for the ToolbarMenu.
| canHaveAnyAttribute | Must return true if the UXML element attributes are not restricted to the values enumerated by uxmlAttributesDescription. |
| uxmlAttributesDescription | Describes the UXML attributes expected by the element. The attributes enumerated here will appear in the UXML schema. |
| uxmlChildElementsDescription | Enumerator to get the child elements of the UxmlTraits of TextElement. |
| focusable | The focusable attribute. |
| focusIndex | The focus index attribute. |
| Init | Initializer for the UxmlTraits for the TextElement. |