Textmate Highlighting: Visual mode selection does not have correct background

Reported by @josemarluedke on discord.

Oni Version: v0.3.7 Operating System: Windows

Issue:

With textmate highlighting active, you see this:

And he also tested out gruvbox dark:

On my machine / config with gruvbox_dark, I see this:

Steps to reproduce:

• This reproduces both with gruvbox_dark and dracula themes

There's potentially an issue with how we're synchronizing colors / schemes to Neovim.