comment code changes when saved

I want to add a button for comment code, but when I save, Post Editor Buttons Forks changes the before to ampersand+l+t+semi-colon+exclamation mark etc… and after changes accordingly. I guess I understand why it does that, but I don’t want it to do it. I want to be able to use the marks in the html such as below.

<!–This is a comment. Comments are not displayed in the browser–>

I hope this plugin continues to get updated. I love it!

https://www.ads-software.com/plugins/post-editor-buttons-fork/