These packages are not in nixpkgs yet (will most likely be added after
the next MELPA import), so they're added here manually.
As both originate from the same source they're added to the same
derivation here by using a custom recipe.
LSP-mode in combination with the Rust language server does not really
work as RLS is extremely unstable.
This switches over to eglot, which automatically restarts RLS after
every crash. From initial testing it seems to be slightly less
annoying than the previous setup.
The stable version does not seem to contain `gfm-view-mode` which is
required by LSP.
If it's not available the side-effect is nasty freezes of the entire
emacs session.
There are several severe regressions from EXWM 0.15 to EXWM 0.17. This
commit pins the version to the somewhat newer 0.18 in hope that it
resolves those issues again.
