message: make `sweep_all` public and document a *bit* better =)
diff: @@ -93,8 +93,8 @@ where
  self.increment_revision();
  }
  - /// See `Database::sweep`.
  - pub(crate) fn sweep_all(&self, db: &DB) {
  + /// Default implementation for `Database::sweep_all`.
  + pub fn sweep_all(&self, db: &DB) {
  // Note that we do not acquire the query lock (or any locks)
  // here. Each table is capable of sweeping itself atomically
  // and there is no need to bring things to a halt. That said,
  