o Add "FreeBSD-users-jp@jp" entry

jauthors.ent

o Merge the following from the English version:

1.89 -> 1.90 book.sgml
1.260 -> 1.264 contrib/chapter.sgml
1.15 -> 1.39 l10n/chapter.sgml

Submitted by: kuriyama, hrs
Reviewed by: hrs
References: [doc-jp 7504]