Bug 1574852 - part 55: Move HTMLEditRules::MakeList() to HTMLEditor r=m_kato

Additionally, this patch makes it use early-return style with `continue` as
far as making number of changing line minimized.

Differential Revision: https://phabricator.services.mozilla.com/D44194

--HG--
extra : moz-landing-system : lando

Author: masayuki-nakano