Remove "not" CSS pseudo-class that always matches
Remove "not" CSS pseudo-class that always matches

The ".systemMessage" class is set on ".comment" elements, but not on
".comments" elements, so ".comments:not(.systemMessage)" is always the
same as ".comments".

Signed-off-by: Daniel Calviño Sánchez <bd7629e975cc0e00ea7cda4ab6a120f2ee42ac1b@gmail.com>

nextcloud/spreed,nextcloud/spreed,nextcloud/spreed