update changelog

CHANGELOG.md

@@ -6,6 +6,7 @@
 * Disallow attribute/prop names from matching two-way-bound names or `{shorthand}` attribute/prop names ([#4325](https://github.com/sveltejs/svelte/issues/4325))
 * Improve performance of `flush()` by not using `.shift()` ([#4356](https://github.com/sveltejs/svelte/pull/4356))
 * Permit reserved keywords as destructuring keys in `{#each}` ([#4372](https://github.com/sveltejs/svelte/issues/4372))
+* Disallow reserved keywords in `{expressions}` ([#4372](https://github.com/sveltejs/svelte/issues/4372))
 * Fix code generation error with precedence of arrow functions ([#4384](https://github.com/sveltejs/svelte/issues/4384))
 
 ## 3.18.1