[authors] PING Gary: Edits to WG Ch6

[Jean Hollis Weber]

While working on the index, I corrected some typos in Ch6 (Intro 
to Styles). I also made a few other changes to follow some 
stylistic changes you've been making in other chapters recently.

The file is in the WG Feedback folder. My apologies for the lack 
of change tracking; I forgot to turn it on.

--Jean