[LyX/master] DocBook: missing multicol test.

[Thibaut Cuvelier]

commit 7c1d4fd3c41a7a99d3cb2eb90b1e7c1eb7e1456f
Author: Thibaut Cuvelier <tcuvelier at lyx.org>
Date:   Sun Sep 26 19:10:22 2021 +0200

    DocBook: missing multicol test.

 .../export/docbook/multicol_doc_ru_additional.lyx  | 1507 ++++++++++++++++++++
 .../export/docbook/multicol_doc_ru_additional.xml  |   77 +
 2 files changed, 1584 insertions(+), 0 deletions(-)