message: Added comment on the constructor fo TopDocSByField
diff: @@ -76,6 +76,11 @@ impl<T: FastValue + PartialOrd + Clone> TopDocsByField<T> {
  /// The given field name must be a fast field, otherwise the collector have an error while
  /// collecting results.
  ///
  + /// This constructor is crate-private. Client are supposed to call
  + /// build `TopDocsByField` object using the `TopDocs` API.
  + ///
  + /// e.g.: `TopDocs::with_limit(2).order_by_field(sort_by_field)`
  + ///
  /// # Panics
  /// The method panics if limit is 0
  pub(crate) fn new(field: Field, limit: usize) -> TopDocsByField<T> {
  