Fix summary of tokio::util::StreamExt
The `throttle` function was not mentioned in the summary block but is listed as a method for the trait.
@@ -13,8 +13,8 @@ pub use util::enumerate::Enumerate;
/// An extension trait for `Stream` that provides a variety of convenient
/// combinator functions.
///
-/// Currently, there only is a [`timeout`] function, but this will increase
-/// over time.
+/// Currently, there are only [`timeout`] and [`throttle`] functions, but
+/// this will increase over time.
///
/// Users are not expected to implement this trait. All types that implement
/// `Stream` already implement `StreamExt`.
