message: Tiny fixup of `Multiple` documentation
diff: @@ -91,7 +91,7 @@ use requests::{ContractRuntimeRequest, NetworkRequest, StorageRequest};
  /// A pinned, boxed future that produces one or more events.
  pub type Effect<Ev> = BoxFuture<'static, Multiple<Ev>>;
  -/// Intended to hold a small collection of [`Effect`](type.Effect.html)s.
  +/// A small collection of rarely more than two items.
  ///
  /// Stored in a `SmallVec` to avoid allocations in case there are less than three items grouped. The
  /// size of two items is chosen because one item is the most common use case, and large items are
  