message: Add comment on why we reinit index repository
diff: @@ -41,6 +41,8 @@ fn load_config(repo: &git2::Repository) -> Result<IndexConfig> {
  impl Index {
  pub(crate) fn new(path: impl AsRef<Path>) -> Result<Self> {
  let path = path.as_ref().to_owned();
  + // This initializes the repository, then closes it afterwards to avoid leaking file descriptors.
  + // See https://github.com/rust-lang/docs.rs/pull/847
  let diff = crates_index_diff::Index::from_path_or_cloned(&path)
  .context("initialising registry index repository")?;
  let config = load_config(diff.repository()).context("loading registry config")?;
  