Hide the Bound type in docs at its deprecated location in std::collections

Author: SimonSapin

Diff for: src/libstd/collections/mod.rs

@@ -421,6 +421,7 @@
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_deprecated(reason = "moved to `std::ops::Bound`", since = "1.26.0")]
+#[doc(hidden)]
 pub use ops::Bound;
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use alloc::{BinaryHeap, BTreeMap, BTreeSet};