[nem-en] [Completion] Filtering of property assessor methods

[vc]

> I guess they have the SpecialName attribute. So you can test if
> (x : IMember).Attributes %&& NemerleAttributes.SpecialName
> is true.
> 
> This handles also other "hidden" / generated members.

Unfortunately this don't work. get_, set_, add_, remove_ methods not marked
by this flag.

For example, "System.Console.?" return many hidden "get_" metods.