change CLASS_NEW_INSTANCE macro to call .new

so that if .new gets overridden, it gets properly called

ext/rbs_extension/ruby_objs.c

@@ -3,7 +3,7 @@
 #ifdef RB_PASS_KEYWORDS
   // Ruby 2.7 or later
   #define CLASS_NEW_INSTANCE(klass, argc, argv)\
-          rb_class_new_instance_kw(argc, argv, klass, RB_PASS_KEYWORDS)
+          rb_respond_to(klass, rb_intern("new")) ? rb_funcallv_kw(klass, rb_intern("new"), argc, argv, RB_PASS_KEYWORDS) : rb_class_new_instance_kw(argc, argv, klass, RB_PASS_KEYWORDS)
 #else
   // Ruby 2.6
   #define CLASS_NEW_INSTANCE(receiver, argc, argv)\