Tiny style improvement for vertical tabs on node forms

Problem:

When creating a node, the pretty new vertical tab node options in the sidebar only open when you actually click on the word. When you click *next* to the word, you still see the pointer cursor, but nothing will happen.

Proposed solution:

Making the title a display: block makes the whole thing clickable.

See also attached screenshot to explain. Attaching patch in comments to include issue-number.