Move the CHANGELOG entry for dart:cli deprecation to 2.15.0

Change-Id: I73bfdd310af6df6cc1d62311e155fc432b84165d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/212567
Commit-Queue: Lasse R.H. Nielsen <lrn@google.com>
Auto-Submit: Lasse R.H. Nielsen <lrn@google.com>
Reviewed-by: Alexander Thomas <athom@google.com>
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d80768..7233909 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -71,6 +71,13 @@
   instance variable, and it brings the implementation behavior in line with
   the specification in all other cases.
 
+### Core libraries
+
+#### `dart:cli`
+
+- The experimental `waitFor` functionality, and the library containing only that
+  function, are now deprecated.
+
 ### Tools
 
 #### Dart command line
@@ -145,11 +152,6 @@
 - Added `void unawaited(Future)` top-level function to deal with the
   `unawaited_futures` lint.
 
-#### `dart:cli`
-
-- The experimental `waitFor` functionality, and the library containing only that
-  function, are now deprecated.
-
 #### `dart:core`
 
 - Introduce `Enum` interface implemented by all `enum` declarations.