message: wording: if -> when
diff: @@ -59,7 +59,7 @@ pub enum Definition {
  /// Defined in an environment variable, includes the environment key.
  Environment(String),
  /// Passed in on the command line.
  - /// A path is attached if the config value is a path to a config file.
  + /// A path is attached when the config value is a path to a config file.
  Cli(Option<PathBuf>),
  }
  