Update src/stream/stream/partial_cmp.rs

Hides docs as standard in our codebase for all Future types

Co-Authored-By: Fedor Sakharov <fedor.sakharov@gmail.com>

Author: assemblaj

src/stream/stream/partial_cmp.rs

@@ -9,7 +9,8 @@ use crate::task::{Context, Poll};
 
 // Lexicographically compares the elements of this `Stream` with those
 // of another.
-#[derive(Debug)]
+#[doc(hidden)]
+#[allow(missing_debug_implementations)]
 pub struct PartialCmpFuture<L: Stream, R: Stream> {
     l: Fuse<L>,
     r: Fuse<R>,
@@ -90,4 +91,4 @@ where
         cx.waker().wake_by_ref();
         Poll::Pending
     }
-}
+}