Add an option to disable Go To Implementation feature in Roslyn API

[dungpa]

Version Used:
Microsoft.CodeAnalysis.EditorFeatures 2.0.0-rc2

Steps to Reproduce:
F# language service in Visual Studio 2017 starts using Roslyn for editor features:

1. Open an F# file in Visual Studio
2. Right click and choose Go To Implementation
3. Nothing happens

Expected Behavior:
One should be able to opt-out and disable Go To Implementation if F# language service doesn't know how to implement Go To Implementation yet.

Actual Behavior:
There is no API in order to hide Go To Implementation feature.

See dotnet/fsharp#1800 (comment) for more details.

[CyrusNajmabadi]

Anything other than GoToImpl?

[dungpa]

Probably also 'Quick Actions and Refactoring (Ctrl + .)' feature if there is not a way to disable that yet.

[CyrusNajmabadi]

Probably also 'Quick Actions and Refactoring (Ctrl + .)' feature

Hrmm... intersting. will have to look into that. That feature isn't controlled by us.

[CyrusNajmabadi]

Ok, i have a fix out for the 'quick actions' menu item. Anything else?

[dungpa]

After checking other menu items, I think that's all for now. Thanks for the quick turn around.

[CyrusNajmabadi]

Ok, you should no longer see "Quick Actions and Refactorings". If/when F# adds support for that, we can make it work by exporting the right set of Languages on SuggestedActionSourceProvider.

[dungpa]

Great, thanks.

[saul]

@dungpa, @CyrusNajmabadi - not sure "Quick Actions and Refactorings" has been disabled? We now have a few code fixes that use this feature I think.