doc: dense set

docs/md/container.md

@@ -63,4 +63,5 @@ implicit list within the packed array itself.
 
 The interface is in all respects similar to its counterpart in the standard
 library, that is, the `std::unordered_set` class.<br/>
-Therefore, there is no need to go into the API description.
+However, this type of set also supports reverse iteration and therefore offers
+all the functions necessary for the purpose (such as `rbegin` and `rend`).