Add less/scss files to getting started

* Add less/scss files to getting started
* NOTE: This merges into the Release branch
Seems like it would make sense to put this above "You can use the same shortcut to edit other things as well", since this is more related to the CSS example than to the other cases. Also, I don't think we need to explain that it works without the preprocessor running. So, maybe we could move it to the end of the first paragraph above - i.e., after "If you hit ESC outside of a quick inline editor, they'll all collapse", you could add "Quick Edit will also find rules defined in LESS and SCSS files, including nested rules."