send videochat-url and -invitation also through header

src/chat.rs

@@ -1636,6 +1636,7 @@ pub async fn send_videochat_invitation(context: &Context, chat_id: ChatId) -> Re
     };
 
     let mut msg = Message::new(Viewtype::VideochatInvitation);
+    msg.param.set(Param::VideochatUrl, &url);
     msg.text = Some(
         context
             .stock_string_repl_str(StockMessage::VideochatInviteMsgBody, url)

src/mimefactory.rs

@@ -875,6 +875,19 @@ impl<'a, 'b> MimeFactory<'a, 'b> {
 
         if self.msg.viewtype == Viewtype::Sticker {
             protected_headers.push(Header::new("Chat-Content".into(), "sticker".into()));
+        } else if self.msg.viewtype == Viewtype::VideochatInvitation {
+            protected_headers.push(Header::new(
+                "Chat-Content".into(),
+                "videochat-invitation".into(),
+            ));
+            protected_headers.push(Header::new(
+                "Chat-Videochat-Url".into(),
+                self.msg
+                    .param
+                    .get(Param::VideochatUrl)
+                    .unwrap_or_default()
+                    .into(),
+            ));
         }
 
         if self.msg.viewtype == Viewtype::Voice

src/param.rs

@@ -68,6 +68,9 @@ pub enum Param {
     /// For Messages
     AttachGroupImage = b'A',
 
+    /// For Messages
+    VideochatUrl = b'V',
+
     /// For Messages: space-separated list of messaged IDs of forwarded copies.
     ///
     /// This is used when a [crate::message::Message] is in the