2272 – synchronized attribute documentation

The synchronized attribute for class methods should be documented somewhere in attribute.html and/or in class.html.
Most importantly it should be mentioned that it represents a monitor operation and thus behaves like in Java or like synchronized(this). There seems to be confusion about that quite often. Additionally the case for static synchronized methods should be mentioned (uses classinfo?).
Since one might assume the synchronized attribute works like the synchronized{} statement one might also assume the synchronized method becomes a distinct critical section. This misunderstanding should also be cleared out in statement.html.

Fixed dmd 1.034 and 2.018