Merge pull request #300750 from amarshall/ruby-cargohash-failure

ruby: improve failure message when missing cargoHash

pkgs/development/interpreters/ruby/default.nix

···
         cargoDeps = if yjitSupport then rustPlatform.fetchCargoTarball {
           inherit (finalAttrs) src;
           sourceRoot = "${finalAttrs.pname}-${version}/${finalAttrs.cargoRoot}";
-          hash = cargoHash;
+          hash = assert cargoHash != null; cargoHash;
         } else null;
 
         postUnpack = opString rubygemsSupport ''