[LyX/master] Update Russian localization

[Yuriy Skalko]

commit 5887601f6836ebf6f2b16cc7587a98cc3aa6c391
Author: Yuriy Skalko <yuriy.skalko at gmail.com>
Date:   Fri Oct 30 23:49:21 2020 +0200

    Update Russian localization

 lib/doc/ru/Additional.lyx |  576 +++++++++++++++++++++++++++------------------
 lib/doc/ru/Intro.lyx      |    2 +-
 lib/doc/ru/Math.lyx       |   17 +-
 lib/doc/ru/Tutorial.lyx   |    2 +-
 po/ru.po                  |    8 +-
 5 files changed, 366 insertions(+), 239 deletions(-)