Clarify that lld package provides unwrapped lld

[matklad]

Description of changes

lld package provides an unwrapped lld. It doesn't always work on NixOS
(eg, it doesn't set rpath), and so dosen't always work.

What one should be using instead is the lld from
llvmPackages.bintools package. This super counterintutive.

One incremental step we can take here is to clarify that the lld
package is unrwapped -- right now, it looks like 100% legit thing one
should be using!

cc #24744.

If someone wants to do a more substantial change (like renaming the package to lld_unwrapped or even removing it altogether), that would be great! I don't have capacity for more invasive change myself though.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• 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/)
• 22.05 Release Notes (or backporting 21.11 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
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[happysalada]

Thank you for this, feel free to ping me if you need a review in the future!