syntax checking: html: don't bother linting empty sections, otherwise in
a plain PHP document, it can show HTML warnings about missing title
r=ericp?

(integrated from komodo (trunk) change 81230 by toddw)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@13365 b87d16e7-d29f-4ee1-b5ec-817d645d335f