message: Use next() instead of nth(0)
diff: @@ -1532,7 +1532,7 @@ fn default_readme_from_package_root(package_root: &Path) -> Option<String> {
  .map(|&fname| package_root.join(Path::new(fname)))
  .filter(|path| path.is_file())
  .flat_map(|path| path.file_name().map(|fname| fname.to_string_lossy().into_owned()))
  - .nth(0)
  + .next()
  }
  /// Checks a list of build targets, and ensures the target names are unique within a vector.
  