message: Add missing `Debug` `impl` for `pidfile`
diff: @@ -20,6 +20,7 @@ use tracing::warn;
  /// an application was shut down cleanly.
  ///
  /// The pidfile is held open with an exclusive but advisory lock.
  +#[derive(Debug)]
  struct Pidfile {
  /// The pidfile.
  ///
  @@ -60,6 +61,7 @@ enum PidfileError {
  ///
  /// High-level description of the outcome of opening and locking the PIDfile.
  #[must_use]
  +#[derive(Debug)]
  enum PidfileOutcome {
  /// Another instance of the node is likely running, or an attempt was made to reuse a pidfile.
  ///
  