This MR uses the rust-analyzer language server which is already included in the Flatpak Rust SDK extenstion. It doesn't much make sense anymore to rely on the host-side language server, since it has following disadvantages:
Because of those reasons I also removed the downloader code, since IMHO it's better to make use of the Flatpak rust-analzyer which is going to be more reliable and gets automatically updated with new Rust SDKs.
This also leads to the question if it makes sense to keep the
rustup plugin integrated in Builder, since we have everything properly in our Flatpak SDK now (
rls got replaced by
rust-analyzer, and in theory we won't need
rustup anymore to install stuff on host side).
Closes #1378 (closed)