fix core::marker::Destruct doc

Author: neeko-cat

library/core/src/marker.rs

@@ -1049,7 +1049,7 @@ marker_impls! {
 
 /// A marker for types that can be dropped.
 ///
-/// This should be used for `~const` bounds,
+/// This should be used for `[const]` bounds,
 /// as non-const bounds will always hold for every type.
 #[unstable(feature = "const_destruct", issue = "133214")]
 #[rustc_const_unstable(feature = "const_destruct", issue = "133214")]