Problem: comment plugin fails toggling if 'cms' contains \
Solution: escape backslash (Maxim Kim)
groff could be commented using \" or \# and comment plugin fails to
uncomment such things.
NOTE: if newstyle comment would be introduced, e.g. .\#
for groff test would need to be adjusted.
closes: #17530
Signed-off-by: Maxim Kim <habamax@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>