Add wysiwyg editors based on file extentions

[mkhanal]

It would be awesome if you can add wysiwyg editors for each type of files (simple ones at least). It should be possible to hook in existing editors like https://www.tinymce.com/

The use case is, when i create some content that I want content creators to edit (not necessarily technical), they should be able to use it to edit yaml/haml/markdown/kramdown... content based on my template

Would be very helpful with Jekyll sites.