Explicitly flag protected class attributes

[antoinetissier]

For classes, there is no difference made between protected and public attributes in the generated doc.

As far as I know, protected in JavaScript is more of a convention than a real enforcement. The language won't prevent you from doing myClassInstance.myProtectedAttribute. So if it's not explicit in the doc, people might introduce bad patterns in their code without even knowing it.

For this reason, I think it would be nice if the generated doc could explicitly flag protected class attributes.