Surface the automatic events from notify properties more clearly

[rictic]

Currently we add a little text annotation on notifyproperties. This is useful for power users who've used Polymer for a while, but I often see folks that want to listen for the automatically generated events but don't know what notify implies.

It'd be helpful for them if we added a tooltip or similar on the notify annotation and had a way to show auto generated events for users curious about them.

[jmstriegel]

+1 It would be super clear for auto generated events to be explicitly listed under the "Events" section of each element's API doc.

[notwaldorf]

We're already saying something like Default: false – readOnly – notifies for these properties, maybe it could be notifies foo-changed instead?

[arthurevans]

I'm with @jmstriegel on this... People look in the Events section for events. The current system works fine for people who know the conventions, but for everyone else, it's just one more unnecessary mystery.

If there's no technical limitation, I'd go with adding them to Events and adding a "Hide generated events" button.