Update changelog

Author: DZakh

CHANGELOG.md

@@ -18,6 +18,7 @@
 - Add popover attributes to JsxDOM.domProps. https://github.com/rescript-lang/rescript/pull/7317
 - Add `inert` attribute to `JsxDOM.domProps`. https://github.com/rescript-lang/rescript/pull/7326
 - Make reanalyze exception tracking work with the new stdlib. https://github.com/rescript-lang/rescript/pull/7328
+- Add built-in support for the JavaScript in operator. https://github.com/rescript-lang/rescript/pull/7342
 
 #### :boom: Breaking Change