synth: drop

The project no longer compiled with Rust 1.90 as it made use
of the removed concat_idents! macro and the project is no longer maintained:
https://github.com/shuttle-hq/synth/issues/455#issuecomment-2730063806

pkgs/by-name/sy/synth/package.nix

@@ -1,34 +0,0 @@
-{
-  lib,
-  rustPlatform,
-  fetchFromGitHub,
-}:
-
-rustPlatform.buildRustPackage rec {
-  pname = "synth";
-  version = "0.6.9";
-
-  src = fetchFromGitHub {
-    owner = "shuttle-hq";
-    repo = "synth";
-    rev = "v${version}";
-    sha256 = "sha256-/z2VEfeCCuffxlMh4WOpYkMSAgmh+sbx3ajcD5d4DdE=";
-  };
-
-  cargoHash = "sha256-sJSU85f4bLh89qo8fojWJNfJ9t7i/Hlg5pnLcxcwKt4=";
-
-  checkFlags = [
-    # https://github.com/shuttle-hq/synth/issues/309
-    "--skip=docs_blog_2021_08_31_seeding_databases_tutorial_dot_md"
-  ];
-
-  # requires unstable rust features
-  RUSTC_BOOTSTRAP = 1;
-
-  meta = with lib; {
-    description = "Tool for generating realistic data using a declarative data model";
-    homepage = "https://github.com/getsynth/synth";
-    license = licenses.asl20;
-    maintainers = [ ];
-  };
-}

pkgs/top-level/aliases.nix

@@ -1492,6 +1492,7 @@ mapAliases {
   syncthing-tray = throw "syncthing-tray has been removed because it is broken and unmaintained"; # Added 2025-05-18
   syncthingtray-qt6 = throw "'syncthingtray-qt6' has been renamed to/replaced by 'syncthingtray'"; # Converted to throw 2025-10-27
   syndicate_utils = throw "'syndicate_utils' has been removed due to a hostile upstream moving tags and breaking src FODs"; # Added 2025-09-01
+  synth = throw "'synth' has been removed because it is unmaintained"; # Added 2025-11-15
   system = warnAlias "'system' has been renamed to/replaced by 'stdenv.hostPlatform.system'" stdenv.hostPlatform.system; # Converted to warning 2025-10-28
   t1lib = throw "'t1lib' has been removed as it was broken and unmaintained upstream."; # Added 2025-06-11
   tamgamp.lv2 = tamgamp-lv2; # Added 2025-09-27