HudToggleKey: Add textures to a whitelist so they don't get hidden

[Tenome]

In my case, I want to see the nice remade tachometers by Darillone, but I want to hide the rest of the HUD.

Also, the "slipstream" texture will get stuck onscreen if you hide the HUD while trailing someone (already been reported elsewhere in this Git), just thought I'd bring that up again. If that happens, just turn the HUD on and off again when not slipstreaming.