Update the AS CHANGELOG

Author: fxn

activesupport/CHANGELOG.md

@@ -1,3 +1,15 @@
+*   `ActiveSupport::Dependencies` no longer installs a `const_missing` hook. Before this, you could push to the autoload paths and have constants autoloaded. This feature, known as the `classic` autoloader, has been removed.
+
+    *Xavier Noria*
+
+*   Private internal classes of `ActiveSupport::Dependencies` have been deleted, like `ActiveSupport::Dependencies::Reference`, `ActiveSupport::Dependencies::Blamable`, and others.
+
+    *Xavier Noria*
+
+*   The private API of `ActiveSupport::Dependencies` has been deleted. That includes methods like `hook!`, `unhook!`, `depend_on`, `require_or_load`, `mechanism`, and many others.
+
+    *Xavier Noria*
+
 *   Improves the performance of ActiveSupport::NumberHelper formatters by avoiding the use of
     exceptions as flow control.
 
@@ -7,8 +19,8 @@
 
     Previously, if you provided a `error_handler` to `redis_cache_store`, any errors thrown by
     the error handler would be rescued and logged only. Removed the `rescue` clause from `handle_exception`
-    to allow these to be thrown. 
-    
+    to allow these to be thrown.
+
     *Nicholas A. Stuart*
 
 *   Allow entirely opting out of deprecation warnings.