Checked Full Site Editing Tag in Classic Theme

[kafleg]

This PR will check if Classic Theme used full-site-editing tag in style.css header or not.

[acosmin]

Looks ok :)

[kafleg]

Thanks for checking @acosmin :)

[justintadlock]

The code changes look pretty good to me (see comment above).

Outside of that, it looks like you need to turn on tabs (instead of spaces) for your code editor. The commit is overwriting the entire file.