fourmolu-checker v1.9.0

• add a read-only Show Fourmolu debug output Quick Fix for current
  check-failed diagnostics; it reruns Fourmolu with --debug using the same
  resolved context, omits stdout and discards stale results;
• keep debug output bounded to Fourmolu stderr in the Output channel without
  changing source files, diagnostics, hovers, previews or failure reports.