property Title on ForumTopicBase

.github/dev.yml

@@ -1,7 +1,7 @@
 pr: none
 trigger: [ master ]
 
-name: 4.2.7-dev.$(Rev:r)
+name: 4.2.9-dev.$(Rev:r)
 
 pool:
   vmImage: ubuntu-latest

src/TL.Xtended.cs

@@ -761,6 +761,9 @@ namespace TL
 	partial class MessageReplyHeader	{ public int TopicID => flags.HasFlag(Flags.forum_topic) ? flags.HasFlag(Flags.has_reply_to_top_id) ? reply_to_top_id : reply_to_msg_id : 0; }
 	partial class GroupCallBase			{ public static implicit operator InputGroupCall(GroupCallBase call) => new() { id = call.ID, access_hash = call.AccessHash }; }
 
+	partial class ForumTopicBase		{ public virtual string Title => null; }
+	partial class ForumTopic			{ public override string Title => title; }
+
 	partial class RequestedPeer			{ public abstract long ID { get; } }
 	partial class RequestedPeerUser		{ public override long ID => user_id; }
 	partial class RequestedPeerChat		{ public override long ID => chat_id; }