Git commits in Moodle 3.5.6 by Adrian Greeve

commit 8bf1ffc9edc1ba30285333e38193b0ed6f8a16cd
Author: Adrian Greeve <abgreeve@gmail.com>
Date:   Fri, 12 Apr 2019 11:01:20 +0800
Tag:    v3.5.6

MDL-62974 mod_lesson: Minor update to html class.