API console in dark theme has no selection highlight color contrast for completions

Created by: sqs

In the API console at https://sourcegraph.com/api/console, after the redesign, there is no visual indication of which item in a completion menu you have selected.

To repro, using the dark color theme, trigger a completion menu and then use the up/down arrows or mouse to hover or select an item. The hovered/selected item does not have any different background color from the others.

This works as expected in the light theme: