How to delete the slash at the end?

Hi!
First thanks you for your plugin, it’s simple and great! Maybe one day you do the same with taxonomy^^

I want to use a custom url and ended by “.html” but when a wrote that, I have a slash at the end of the url… Do you know how i can delete this?

https://wordpress.org/plugins/simple-post-type-permalinks/