Add HTML comments for region template suggestions

The theme hook suggestions are awesome, but if you are looking at the HTML source code, it can be a little confusing where the HTML is coming from.

This is even more true with the region--no-wrapper.tpl.php file, which adds no HTML tags at all, as opposed to the default region.tpl.php which adds a wrapper HTML tag which you can at least do a global search to try to find.

If we add a

at the end, that might help.