doc/rl-2505: fix links in lib section

- The `virtualisation.hypervGuest.videoMode` option has been removed. Standard tooling can now be used to configure display modes for Hyper-V VMs.

- [`lib.packagesFromDirectoryRecursive`] now rejects unknown arguments.

  [`lib.packagesFromDirectoryRecursive`]: https://nixos.org/manual/nixpkgs/stable/#function-library-lib.filesystem.packagesFromDirectoryRecursive

- [`lib.packagesFromDirectoryRecursive`](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.filesystem.packagesFromDirectoryRecursive) now rejects unknown arguments.

- The `godot-export-templates` package now has its content at `share/godot/export_templates/$version` instead of the output root. This makes it more convenient for for symlinking into `~/.local`, but scripts expecting the old layout will need to be changed.

### Additions and Improvements {#sec-nixpkgs-release-25.05-lib-additions-improvements}

- [`lib.packagesFromDirectoryRecursive`] can now construct nested scopes matching the directory tree passed as input.

- [`lib.packagesFromDirectoryRecursive`](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.filesystem.packagesFromDirectoryRecursive) can now construct nested scopes matching the directory tree passed as input.