alloc/arena: forward reset calls to underlying store of owned arena

alloc/arena.hpp

@@ -75,7 +75,6 @@ namespace cruft::alloc {
             };
         }
 
-
     private:
         T &m_store;
     };
@@ -112,6 +111,10 @@ namespace cruft::alloc {
         decltype(auto) unique (ArgsT &&...args)
         { return m_arena.template unique<T,ArgsT...> (std::forward<ArgsT> (args)...); }
 
+        template <typename ...Args>
+        decltype(auto) reset (Args&&...args)
+        { return m_store.reset (std::forward<Args> (args)...); }
+
     private:
         AllocT m_store;
         arena<AllocT> m_arena;