Usability improvements to {doc,cg}-section.sh and corresponding section of CG. (issue 5342043)

[Carl . D . Sorensen]

The .sh scripts did not upload properly since they have a bad mime-type
in git-cl.

I have edited git-cl, but I can't push it because I don't have git
access.

I'll post a patch on the lilypond issue

http://codereview.appspot.com/5342043/