add a proof

Author: zloirock

CHANGELOG.md

@@ -3,7 +3,7 @@
 - [`Iterator` sequencing proposal](https://github.com/tc39/proposal-iterator-sequencing):
   - Built-ins:
     - `Iterator.concat`
-  - Moved to stable ES, November 2025 TC39 meeting
+  - Moved to stable ES, [November 2025 TC39 meeting](https://github.com/tc39/proposals/commit/33be3cb6d6743c7cc8628c547423f49078c0b655)
   - Added `es.` namespace modules, `/es/` and `/stable/` namespaces entries
 - Fixed increasing `.size` in `URLSearchParams.prototype.append` polyfill in IE8-
 - Compat data improvements: