Remove incorrect error behavior from ready_chunks docs (#2687)

Unlike `TryStream::try_chunks`, which has similar documentation and can
handle `Some(Err(_))` specially, `Stream::ready_chunks` does not and
cannot know whether the stream item represents an error condition, and
does not include any code to return early on an error.

Author: jongiddy

futures-util/src/stream/stream/mod.rs

@@ -1513,8 +1513,7 @@ pub trait StreamExt: Stream {
     /// be immediately returned.
     ///
     /// If the underlying stream ended and only a partial vector was created,
-    /// it'll be returned. Additionally if an error happens from the underlying
-    /// stream then the currently buffered items will be yielded.
+    /// it will be returned.
     ///
     /// This method is only available when the `std` or `alloc` feature of this
     /// library is activated, and it is activated by default.