compose window notifications not working in Thunderbird 93.0beta+
Summary
The check for unrendered markdown's notification box does not appear in the compose window. When unrendered markdown is present, this causes sending to fail.
Steps to reproduce
Use Thunderbird 93.0beta and up. Write an email with markdown, do not render. Click the Send button. Nothing happens and the Send button gets disabled.
Versions
Thunderbird version: 95.0beta2 Markdown Here Revival version: 3.2.9 Operating system: Linux