message: Add some struct field documentation
diff: @@ -18,14 +18,19 @@ mod tests;
  /// A typechecked and elaborated module
  pub struct CheckedModule {
  + /// The name of the module
  pub name: String,
  + /// The definitions contained in the module
  pub definitions: Vec<CheckedDefinition>,
  }
  /// A typechecked and elaborated definition
  pub struct CheckedDefinition {
  + /// The name of the definition
  pub name: String,
  + /// The elaborated value
  pub term: RcValue,
  + /// The type of the definition
  pub ann: RcType,
  }
  