message: Fix a Clippy issue
diff: @@ -557,7 +557,7 @@ where
  effects
  }
  }
  - Event::IsBonded(None, fs, true) => {
  + Event::IsBonded(None, _fs, true) => {
  // Unknown block but validator is bonded.
  // We should finalize the same block eventually. Either in this or in the
  // next era.
  