Fixes #3961: Documentation is missing some more level 2 headers
Merge pull request #28 from jooooooon/bug_3961/documentation_is_missing_some_more_level_2_headers

Fixes #3961: Documentation is missing some more level 2 headers
Merge branch 'branches/rudder/2.4' into branches/rudder/2.6
Merge branch 'branches/rudder/2.6' into branches/rudder/2.7

Conflicts:
	12_upgrade/20_upgrade_centos_rhel.txt