fix rustdoc for IndexedParallelIterator::fold_chunks
@@ -2429,8 +2429,13 @@ pub trait IndexedParallelIterator: ParallelIterator {
///
/// This works essentially like:
///
+ /// ```text
/// iter.chunks(chunk_size)
- /// .map(|chunk| chunk.into_iter().fold(identity, fold_op)),
+ /// .map(|chunk|
+ /// chunk.into_iter()
+ /// .fold(identity, fold_op)
+ /// )
+ /// ```
///
/// except there is no per-chunk allocation overhead.
///
