update ancient note

library/std/src/collections/hash/set.rs

@@ -65,8 +65,8 @@ use super::map::{map_try_reserve_error, RandomState};
 /// ```
 ///
 /// The easiest way to use `HashSet` with a custom type is to derive
-/// [`Eq`] and [`Hash`]. We must also derive [`PartialEq`], this will in the
-/// future be implied by [`Eq`].
+/// [`Eq`] and [`Hash`]. We must also derive [`PartialEq`],
+/// which is implied by [`Eq`].
 ///
 /// ```
 /// use std::collections::HashSet;