Add IsSuggestionMode to AutoCompleteResponse for determining when the completion list should commit aggressively

[DustinCampbell]

Related to dotnet/vscode-csharp#1524

[filipw]

great find!
I think SuggestionModeItem can have its own DisplayText, should that be forwarded to the caller too?

[DustinCampbell]

The intention here is to able to determine when the completion list is in suggestion mode and shouldn't have define commit characters.

It's a bit heavy to add the values of SuggestionModeItem to every AutoCompleteResponse and I'm not sure how I'd even present that in VS Code. I'm working on a new '/completion' end point that we can use for future completion work that should marry a bit better with @david-driscoll's LSP work.

[filipw]

👍👍

[DustinCampbell]

Thanks!