WG3.4 Ch11 Mail Merge needs detailed checking

I have made some minor changes to the Writer Guide chapter on Mail
Merge, but all the instructions still need to be checked thoroughly.

John, when you get to that chapter, please use my version, which is here:
http://www.odfauthors.org/libreoffice/english/writer-guide/draft-lo3.4/wg3.4-ch11-mail-merge/view

--Jean

I just noticed that John had already done this chapter, and he had
already taken care of the things I had spotted. Well done! I should
soon have this chapter ready for publication.

--Jean