docs: Remove <refsectX> from doc comments
docs: Remove <refsectX> from doc comments

gtk-doc now supports Markdown headers with link IDs:
    ## Title ## {#id}

This allows us to exchange more XML markup for Markdown, since we don't
have to write these whole blocks in XML anymore.

wmvanvliet/Chimara,wmvanvliet/Chimara,wmvanvliet/Chimara,wmvanvliet/Chimara,wmvanvliet/Chimara