lib.extendMkDerivation: add a release note entry

nixos/doc/manual/release-notes/rl-2411.section.md

@@ -18,6 +18,12 @@
 
 - NixOS now has support for *automatic boot assessment* (see [here](https://systemd.io/AUTOMATIC_BOOT_ASSESSMENT/)) for detailed description of the feature) for `systemd-boot` users. Available as [boot.loader.systemd-boot.bootCounting](#opt-boot.loader.systemd-boot.bootCounting.enable).
 
+- [`lib.customisation.extendMkDerivation`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.customisation.extendMkDerivation) and [`lib.customisation.adaptMkDerivation`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.customisation.adaptMkDerivation) are introduced to bring [fixed-point arguments](https://nixos.org/manual/nixpkgs/unstable#chap-build-helpers-finalAttrs) support (capability to take `(finalAttrs: { ... })`) to arguments aside from `stdenv.mkDerivation`.
+
+  `lib.extendMkDerivation` helps define a new build helper supporting (`(finalAttrs: { ... })`) based on another build helper with such support, while `lib.adaptMkDerivation` helps existing build helpers with arguments unable to pass to the base build helper (usually `stdenv.mkDerivation`) to adopt fixed-point arguments support with slight expression changes.
+
+  See [Nixpkgs Manual chapter *Fixed-point arguments of build helpers*](https://nixos.org/manual/nixpkgs/unstable#chap-build-helpers-finalAttrs) for details.
+
 ## New Services {#sec-release-24.11-new-services}
 
 - [FlareSolverr](https://github.com/FlareSolverr/FlareSolverr), proxy server to bypass Cloudflare protection. Available as [services.flaresolverr](#opt-services.flaresolverr.enable) service.