message: Correct error message on `PidFileError`
diff: @@ -36,7 +36,7 @@ pub struct PidFile {
  #[derive(Debug, Error)]
  pub enum PidFileError {
  /// The pidfile could not be opened at all.
  - #[error("could not pidfile: {0}")]
  + #[error("could not open pidfile: {0}")]
  CouldNotOpen(#[source] io::Error),
  /// The pidfile could not be locked.
  #[error("could not lock pidfile: {0}")]
  