doc/release-notes: Add section on lib

(cherry picked from commit 2906c69534)

nixos/doc/manual/release-notes/rl-2405.section.md

@@ -759,3 +759,50 @@ Use `services.pipewire.extraConfig` or `services.pipewire.configPackages` for Pi
 - Lisp modules: previously deprecated interface based on `common-lisp.sh` has now been removed.
 
 - The `systemd-confinement` module extension is now compatible with `DynamicUser=true` and thus `ProtectSystem=strict` too.
+
+
+## Nixpkgs Library {#sec-release-24.05-nixpkgs-lib}
+
+### Additions and Improvements {#sec-release-24.05-lib-additions-improvements}
+
+New functions:
+- [`lib.asserts.assertEachOneOf`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.asserts.assertEachOneOf): Check that each value is one of the allowed ones.
+- [`lib.attrsets.longestValidPathPrefix`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.attrsets.longestValidPathPrefix): The longest prefix of an attribute path that refers to an existing attribute in a nesting of attribute sets.
+- [`lib.attrsets.mapCartesianProduct`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.attrsets.mapCartesianProduct): Apply a function to the cartesian product of attribute set value combinations.
+- [`lib.trivial.xor`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.trivial.xor): Boolean "exclusive or"
+- [`lib.lists.ifilter0`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.lists.ifilter0): Filter a list for elements that satisfy a predicate function. The predicate function is called with both the index and value for each element.
+- [`lib.lists.sortOn`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.lists.sortOn): Sort a list based on the default comparison of a derived property.
+- [`lib.path.hasStorePathPrefix`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.path.hasStorePathPrefix): Whether a [path](https://nixos.org/manual/nix/stable/language/values.html#type-path) has a [store path](https://nixos.org/manual/nix/stable/store/store-path.html#store-path) as a prefix.
+- [`lib.filesystem.packagesFromDirectoryRecursive`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.filesystem.packagesFromDirectoryRecursive): Transform a directory tree containing package files suitable for `callPackage` into a matching nested attribute set of derivations.
+- [`lib.fileset.toList`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.fileset.toList): The list of file paths contained in a given file set.
+- [`lib.fileset.maybeMissing`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.fileset.maybeMissing): Create a file set from a path that may or may not exist.
+- [`lib.derivations.optionalDrvAttr`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.derivations.optionalDrvAttr): Conditionally set a derivation attribute.
+- [`lib.strings.makeIncludePath`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.strings.makeIncludePath): Construct an include search path (such as `C_INCLUDE_PATH`) containing the header files for a set of packages or paths.
+
+Improvements:
+- [`lib.fixedPoints.extends`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.fixedPoints.extends): Better documentation
+- [`lib.customisation.makeScope`](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.customisation.makeScope): Better documentation
+- [`lib.derivations.lazyDerivation`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.derivations.lazyDerivation): Now supports multiple outputs with an `outputs` argument
+- [`lib.gvariant`](https://nixos.org/manual/nixpkgs/unstable#sec-functions-library-gvariant): Better error message for integers and attribute set values
+- [`lib.filesets.gitTracked`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.fileset.gitTracked): Now works within store paths
+
+Misc:
+- The [`lib/` directory](https://github.com/NixOS/nixpkgs/tree/release-24.05/lib) is a self-contained flake now, including a working [`lib.trivial.version`](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.trivial.version) (but note that fetching a subtree by itself is not supported in Nix yet)
+- [Various minor performance improvements](https://github.com/NixOS/nixpkgs/issues?q=author%3Aadisbladis+label%3A%226.topic%3A+lib%22+created%3A%3C2024-05-31+)
+
+Module System:
+- New types:
+  - [`types.attrTag`](https://nixos.org/manual/nixos/unstable/#sec-option-types-sums): A tagged union type
+  - `types.nonEmptyListOf`: A non-empty list
+- Improved types:
+  - `types.uniq`/`unique` now check the wrapped type
+
+### Deprecations {#sec-release-24.05-lib-deprecations}
+
+- [`lib.options.mdDoc`](https://nixos.org/manual/nixpkgs/unstable#function-library-lib.options.mdDoc) is obsolete and now emits a warning. The core ecosystem has completely migrated to markdown, so marking markdown as markdown is redundant.
+- `lib.attrsets.zipWithNames` is now a deprecated alias of [`lib.attrsets.zipAttrsWithNames`](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.attrsets.zipAttrsWithNames)
+- `lib.attrsets.cartesianProductOfSets` has been renamed to [`lib.attrsets.cartesianProduct`](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.attrsets.cartesianProduct)
+
+### Internal {#sec-release-24.05-lib-internal}
+- `lib` now has [Readme for contributing](https://github.com/NixOS/nixpkgs/tree/master/lib#readme).
+- Some function's documentation is now written using the [accepted doc comment syntax](https://github.com/NixOS/rfcs/pull/145).