update changelog

Author: RobinMalfait

CHANGELOG.md

@@ -27,6 +27,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - _Experimental_: Do not wrap comment nodes in `@layer` when running codemods ([#14517](https://github.com/tailwindlabs/tailwindcss/pull/14517))
 - _Experimental_: Ensure we don't lose selectors when running codemods ([#14518](https://github.com/tailwindlabs/tailwindcss/pull/14518))
 - _Experimental_: inject `@import` in a more expected location when running codemods ([#14536](https://github.com/tailwindlabs/tailwindcss/pull/14536))
+- Improve `@tailwindcss/postcss` performance for initial builds ([#14565](https://github.com/tailwindlabs/tailwindcss/pull/14565))
 
 ## [4.0.0-alpha.25] - 2024-09-24