update changelog

docs/pages/resources/changelog.md

@@ -15,6 +15,7 @@ New versions of Shoelace are released as-needed and generally occur when a criti
 ## Next
 
 - Added support for using `<sl-dropdown>` in `<sl-breadcrumb-item>` default slot [#2015]
+- Added the `countdown` attribute to `<sl-alert>` to show a visual indicator before the toast disappears [#1899]
 - Fixed a bug that caused errors to show in the console when components disconnect before before `firstUpdated()` executes [#2127]
 - Fixed a bug that made pagination work incorrectly in `<sl-carousel>` [#2155]