Add ISO section number to `Module#===`.

src/class.c

@@ -2191,7 +2191,7 @@ mrb_init_class(mrb_state *mrb)
   mrb_define_method(mrb, mod, "const_missing",           mrb_mod_const_missing,    MRB_ARGS_REQ(1));
   mrb_define_method(mrb, mod, "method_defined?",         mrb_mod_method_defined,   MRB_ARGS_REQ(1)); /* 15.2.2.4.34 */
   mrb_define_method(mrb, mod, "define_method",           mod_define_method,        MRB_ARGS_ARG(1,1));
-  mrb_define_method(mrb, mod, "===",                     mrb_mod_eqq,              MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, mod, "===",                     mrb_mod_eqq,              MRB_ARGS_REQ(1)); /* 15.2.2.4.7 */
 
   mrb_undef_method(mrb, cls, "append_features");
   mrb_undef_method(mrb, cls, "extend_object");