GHCJS Compatibility?

## Summary
Is Haskell Language Server compatible with GHCJS?

## Details
I am currently working on a GHCJS project with miso (https://github.com/dmjio/miso), which exposes a subset of its modules to GHCJS projects, and a different subset to GHC projects. When using HLS, I find that it only uses GHC to resolve dependencies, so the miso modules exposed to GHCJS projects are not discoverable by HLS. This results HLS incorrectly reporting invalid import errors.

I'm not sure if GHCJS is already supported, or if it's feasible to implement support. My initial question is to ask whether it's possible to use GHCJS instead of GHC with HLS? I noticed that `hie-bios` recently added support for a `with-ghc` option -- would that help in any way?

## My Development Environment
I am currently using HLS with GHC 8.10.1 via Nix (`NixOS/nixpkgs#master`): `haskell.packages.ghc8101.ghcWithHoogle (p: [p.haskell-language-server])`.

Thank you,
Dhruv Dang