net: clarify the drop behavior of unix::OwnedWriteHalf (#7742)

tokio/src/net/unix/stream.rs

@@ -974,7 +974,7 @@ impl UnixStream {
     /// Unlike [`split`], the owned halves can be moved to separate tasks, however
     /// this comes at the cost of a heap allocation.
     ///
-    /// **Note:** Dropping the write half will shut down the write half of the
+    /// **Note:** Dropping the write half will only shut down the write half of the
     /// stream. This is equivalent to calling [`shutdown()`] on the `UnixStream`.
     ///
     /// [`split`]: Self::split()