SendMarkdownMessageEffect
Deprecated
Sends a string for Telegram to parse; foreign text in it must be escaped and can fail the whole message. Build the body with `message { }` and use SendMessageEffect.
A message sent as a legacy-Markdown string, the way every message was sent before entities.
A separate effect rather than a flag, because it is a different request: parse_mode asks Telegram to find markup inside the text, and entities tell it where the markup is. Keeping them apart means the deprecation is a type that disappears, not a branch somebody forgets to delete — and means a bot that still sends hand-written Markdown keeps rendering exactly as it did while it migrates, instead of having its asterisks silently become literal.
Whatever is in text is still parsed by Telegram, so foreign text in it still has to be escaped, and unbalanced markup still fails the whole message. That is the defect MessageText removes.