Add policy list room type

include/mtx/events/create.hpp

@@ -27,6 +27,8 @@ struct PreviousRoom
 namespace room_type {
 //! The room type for a space.
 constexpr std::string_view space = "m.space";
+//! MSC for policy list rooms, see https://github.com/matrix-org/matrix-spec-proposals/pull/3784
+constexpr std::string_view exp_policy = "support.feline.policy.lists.msc.v1";
 }
 
 //! Content of the `m.room.create` event.