extend changelog

CHANGELOG.md

@@ -111,8 +111,11 @@ With this release, we dropped support for Coq 8.9.
   an authoritative, monotonically-increasing `nat` with a proposition giving a
   persistent lower bound. See `base_logic.lib.mnat` for further details.
 * Add a class, `Duplicable`, for duplicable propositions. The lemmas
-  `intuitionistically_sep_dup` and `plainly_sep_duplicable` are now instances. A
-  few lemmas are changed to use the new class: `inv_combine_dup_l`,
+  `intuitionistically_sep_dup`, `persistently_sep_dup`,
+  `plainly_sep_duplicable`, and `persistent_sep_dup` are now instances. This
+  means they are now uni-directional; use `duplicable_equiv` to obtain the
+  bidirectional version.
+  A few lemmas are changed to use the new class: `inv_combine_dup_l`,
   `big_sepL_dup`, `big_sepM_dup`, `big_sepS_dup`. Instead of having `□ (P -∗ P ∗
   P)` as an assumption these lemmas now assume `P` to be an instance of
   `Duplicable`.