#810 Enhance Changed and New markers in the documentation

[Jon Wolfers]

It is good to have the *CHG* and *NEW* markers in the documentation.

It would be nice to differentiate them more from the surrounding text as it can be difficult for the eye to distinguish them.

A couple of possibilities that come to mind
1) Have icons for Change and New so they are semi-pictorial
2) Have them appear in a different style, perhaps bold superscript, perhaps with a different colour

There may be other better ways to do this - I don't know what is possible and easy to achieve.