nix: use mold-wrapped for linking

This version of mold can correctly find external system libraries if needed.
buck2 happily works anyway because the flake doesn't depend on system libraries,
but the previous version was still wrong.

Signed-off-by: Austin Seipp <aseipp@pobox.com>

flake.nix

@@ -37,7 +37,7 @@
           IOKit
           Security
         ]);
-        packages = [ pkgs.cargo-bloat my-rust-bin pkgs.mold pkgs.reindeer pkgs.lld_16 pkgs.clang_16 ];
+        packages = [ pkgs.cargo-bloat my-rust-bin pkgs.mold-wrapped pkgs.reindeer pkgs.lld_16 pkgs.clang_16 ];
         shellHook = 
           ''
             export BUCK2_BUILD_PROTOC=${pkgs.protobuf}/bin/protoc