move the scope level key fully inside the scope object

actionpack/lib/action_dispatch/routing/mapper.rb

@@ -1654,7 +1654,7 @@ def with_exclusive_scope
           end
 
           def with_scope_level(kind)
-            @scope = @scope.new(:scope_level => kind)
+            @scope = @scope.new_level(kind)
             yield
           ensure
             @scope = @scope.parent
@@ -1928,6 +1928,10 @@ def new(hash)
           self.class.new hash, self
         end
 
+        def new_level(level)
+          new(:scope_level => level)
+        end
+
         def [](key)
           @hash.fetch(key) { @parent[key] }
         end