json-schema: print the validated schema

The validation process may modify the supplied JSON and it's useful for
debugging purposes to visualise any defaulted values.

tools/json-schema.cpp

@@ -54,6 +54,8 @@ main (int argc, char **argv) {
         auto input  = json::tree::parse (util::view{input_src} .cast<const char*>());
 
         json::schema::validate (*input, schema->as_object ());
+
+        std::cout << *input << '\n';
     } catch (const json::error &e) {
         std::cerr << "error: " << e.what () << '\n';
         return EXIT_FAILURE;