User menu items need decent selectors/ids

At the moment the User Menu, and its menu items are dynamically created but they have no useful selector attributes (e.g. class, data, or id).
This makes them very difficult to interact with in JavaScript.

It would be very helpful if we added some form of identification to the list item, or failing that, the anchor.
I imagine that this could be as simple as the language string used:

<li role="presentation" data-title="mymoodle,admin">

This will require changes in user_get_user_navigation_info(), and in the user_menu() output renderer.