Add feature to disable or grey-out obsolete/deprecated C# methods, attributes, etc on autocomplete

[CanisLupus]

[@DustinCampbell recommended, a few weeks ago, that I post the request here also. Originally in dotnet/vscode-csharp#1109]

I couldn't find a setting for this, nor find results about it on Google. It would be really helpful to avoid auto-completing obsolete stuff when using an API that has legacy methods and attributes. In VSCode, greying out things marked Obsolete (and showing them last in the autocomplete list) - or maybe even being able to disable them - would be great.

Thanks,
Daniel

[Pilchie]

I thought we used to do this in the native language service...

[DustinCampbell]

Not that I'm aware of. We did it in VB for IntelliSense in Zone, but never did anything for C#.

[sharwell]

Consolidating multiple requests in this area to design issue #26488