run formatter in language_server app

Path.wildcard is not working on umbrella level

Author: lukaszsamson

.github/workflows/ci.yml

@@ -91,4 +91,5 @@ jobs:
       - name: Restore timestamps to prevent unnecessary recompilation
         run: IFS=$'\n'; for f in $(git ls-files); do touch -d "$(git log -n 1 --pretty='%cI' -- $f)" "$f"; done
       - run: mix format --check-formatted
+      - run: cd apps/language_server && mix format --check-formatted
       - run: mix dialyzer_vendored