Yay for Sass! 

Returns after commas, and added spaces after each selector. (it's Sass, let them breath since they're going to get compiled anyway)
```scss
.clear,
.entry-content,
.comment-content,
.site-header,
.site-content,
.site-footer {
  &:before,
  &:after {
    @include clearfix;
  }
}
```