Project: moodle
Issue MDL-41438: Change core renderer methods to produce plain headings by default. 
2 functions in the core renderer need some changes so that by default they do not add the 'main' class to headings and so that the level can be specified for heading_with_help. This would need documenting in themes/upgrade.txt and all uses of .main class in all core themes updated to work without it.
Story points: 2