Visual Studio IntelliSense completion list selection needs more contrast / can't be customised

[flcdrg]

Issue Description

The pop-up list that appears when using completion in the text editor of Visual Studio doesn't have much contrast between the selected line and other lines - particularly when using the keyboard (it is a bit better when using the mouse).

eg. In this screenshot, the "something else" item is selected, but it is very subtle.

More contrast would be good, but also it should be possible to customise the colours through Visual Studio's Options menu - either by adding additional entries for SpecFlow, or by selecting existing entries that match the use of the list.

[flcdrg]

May be worth looking at https://github.com/microsoft/VSSDK-Extensibility-Samples/tree/master/AsyncCompletion as an approach for VS2019+