Feature request: add support for .canvas files as folder index, not only .md

[vladstudio]

So I created a "Todo" folder and tried to make Todo.canvas to see if Folder Note would recognize it as an index file. It didn't - It created Todo.md instead, so the file tree looks like this:

But also, the plugin hides todo.canvas from Obsidian, so it looks like this:

It'd be great to be able to use .canvas files as index, not only .md. Thanks!

[berot3]

https://github.com/LostPaul/obsidian-folder-notes has this... FYI