[authors] Writer Guide Ch 11 (Using Mail Merge) revised

[Jean Hollis Weber]

Peter Hillier-Brook has reorganised and rewritten parts of Writer 
Guide Ch 11 (Using Mail Merge), consolidating information about 
mail merge for letters and other documents, envelopes, and 
mailing labels. I've done some minor editing on his work.

I have also cut out of WG Ch5 (Printing, Faxing, Exporting, and 
E-mailing) the info on mail merge for envelopes and mailing 
labels, and referred readers to Ch11 for that info.

Both chapters are on the Review List.

--Jean