haskellPackages.httpClientMultipart: Do not build haddocks

This package now has no modules, so there is no documentation to build.
The library itself is deprecated, and should probably be removed from
nixpkgs soon.

pkgs/development/libraries/haskell/http-client-multipart/default.nix

@@ -11,4 +11,6 @@ cabal.mkDerivation (self: {
     license = self.stdenv.lib.licenses.mit;
     platforms = self.ghc.meta.platforms;
   };
+  # This library now contains now modules as it is deprecated.
+  noHaddock = true;
 })