Support SCSS one line comments

[minimalweb]

I'd like to be able to use this kind of comments in SCSS files:

// doc
// ---
// title: Alert
// name: alert
// category: basics
// ---
//
// ```html_example
// <div class = "alert"> Hello </ div>
// ```

This is related to #175 and #183

SASS style comments do work (even in SCSS files) but are invalid SCSS syntax, so this is not an option.

//doc
  ---
  title: Alert
  name: alert
  category: basics
  ---

  ```html_example
  <div class = "alert"> Hello </ div>

[jdcantrell]

There is some difficulty with this. In order to parse these comments you have to find all lines in a row starting with // and then strip the // from each line. I'm going to leave this open for now. I'm open for PRs to do this.

[infinityrobot]

It looks like this may have been addressed in the solution proposed by @b2l in #235?