Address review comments

src/raw/mod.rs

@@ -3850,9 +3850,10 @@ impl<T> RawIterRange<T> {
  /// Folds every element into an accumulator by applying an operation,
  /// returning the final result.
  ///
- /// `fold_impl()` takes three arguments: a number of items in the table, an initial value,
- /// and a closure with two arguments: an 'accumulator', and an element. The closure
- /// returns the value that the accumulator should have for the next iteration.
+ /// `fold_impl()` takes three arguments: the number of items remaining in
+ /// the iterator, an initial value, and a closure with two arguments: an
+ /// 'accumulator', and an element. The closure returns the value that the
+ /// accumulator should have for the next iteration.
  ///
  /// The initial value is the value the accumulator will have on the first call.
  ///
@@ -3877,10 +3878,6 @@ impl<T> RawIterRange<T> {
  where
  F: FnMut(B, Bucket<T>) -> B,
  {
- if n == 0 {
- return acc;
- }
-
  loop {
  while let Some(index) = self.current_group.next() {
  // The returned `index` will always be in the range `0..Group::WIDTH`,