Change file extension to something other than restructured text

[jamesjarvis]

Then you can add it to https://github.com/github/linguist/blob/master/lib/linguist/languages.yml, so GitHub will classify risotto files

[raphaelvigee]

I definitely plan to change the extension. I wont be able to add it to the linguist as it violates the first rule of the checklist:

The extension of the new language is used in hundreds of repositories on GitHub.com.

[jamesjarvis]

Sad risotto noise