i18n-ru: fix RST breakage spotted by test-gendoc
test-gendoc complained:
% extracting documentation from ru
checking for parse errors
+ gendoc-ru.txt:5686: (WARNING/2) Field list ends without a blank
line; unexpected unindent.
+ gendoc-ru.txt:8327: (WARNING/2) Definition list ends without a
blank line; unexpected unindent.
(binary:application/octet-stream)