haskellPackages.os-string: mark os-string as GHC-9.10 Core library

[ymeister]

Description of changes

os-string became part of GHC Core libraries in 9.10 - https://gitlab.haskell.org/ghc/ghc/-/tree/ghc-9.10.1-release/libraries?ref_type=tags .
Without it marked as such, it causes indirect dependency on multiple versions.
Example hashable-1.4.7.0:

    This package indirectly depends on multiple versions of the same package. This is very likely to cause a compile failure.
      package filepath (filepath-1.5.2.0-inplace) requires os-string-2.0.2-inplace
      package hashable (hashable-1.4.7.0) requires os-string-2.0.2.2-Kefn0a7sWMV12dRa14fuvx

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 24.11 Release Notes (or backporting 23.11 and 24.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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[maralorn]

Great, thanks!