languages.registerHoverProvider doesn't work with vsls scheme files

[eamodio]

Describe what happened:

This is probably similar to #1333, but languages.registerHoverProvider registered by the guest on vsls schemes doesn't provide a callback to provideHover.

I'm trying to get GitLens inline blame hovers to work in a Live Share guest, and GitLens uses languages.registerHoverProvider to add hovers to its inline blame decoration (and for the other editor annotations).

What was your system configuration?
Product and Version [VS/VSCode]: VSCode
OS Version[macOS/Windows]: Windows
Live Share Extension Version: 1.0.5857
Target Platform or Language [e.g. Node.js]:

[eamodio]

@lostintangent Any response at all here?