Notify editors about h1, h2 usage and automatic conversion happening

Create wiki page in creole format with several headers Make sure headers are displayed as <h3> and below, TOC and section edit links work Repeat in nwiki format Create wiki page in html format using Atto, insert headers of different levels Make sure headers are displayed as entered and TOC and section edit links work Create wiki page in html format using TinyMCE, insert headers of different levels Make sure you get a warning when saving (only if you used h1 or h2) and the headings levels are properly adjusted (h1->h3; h2->h4; h3->h5; h4, h5, h6 -> h6), make sure TOC and section edit links work