document HACKs

library/std/src/io/buffered/bufreader.rs

@@ -21,6 +21,7 @@
 /// unwrapping the `BufReader<R>` with [`BufReader::into_inner`] can also cause
 /// data loss.
 ///
+// HACK(#78696): can't use `crate` for associated items
 /// [`TcpStream::read`]: super::super::super::net::TcpStream::read
 /// [`TcpStream`]: crate::net::TcpStream
 ///

library/std/src/io/buffered/bufwriter.rs

@@ -59,6 +59,7 @@
 /// together by the buffer and will all be written out in one system call when
 /// the `stream` is flushed.
 ///
+// HACK(#78696): can't use `crate` for associated items
 /// [`TcpStream::write`]: super::super::super::net::TcpStream::write
 /// [`TcpStream`]: crate::net::TcpStream
 /// [`flush`]: BufWriter::flush