Add Stream alias for AsyncIterator

library/core/src/async_iter/async_iter.rs

@@ -12,6 +12,7 @@
 /// [impl]: index.html#implementing-async-iterator
 #[unstable(feature = "async_iterator", issue = "79024")]
 #[must_use = "async iterators do nothing unless polled"]
+#[doc(alias = "Stream")]
 pub trait AsyncIterator {
     /// The type of items yielded by the async iterator.
     type Item;