[LyX/2.3.x] ja.po: translation update from Koji Yokota

[Scott Kostyshak]

commit 5a811f5002187fb033e3ec4fc3712d3ca239b3a7
Author: Scott Kostyshak <skost...@lyx.org>
Date:   Thu Aug 31 01:11:05 2017 -0400

    ja.po: translation update from Koji Yokota
    
    I checked that the changes from 29378af4 are preserved.

 po/ja.po | 3702 ++++++++++++++++++++++----------------------------------------
 1 files changed, 1284 insertions(+), 2418 deletions(-)