Return the sectioning entry for the current headline.
LEVEL is the reduced level of the headline.
TEXT is the text of the headline, everything except the leading stars.
The return value is a cons cell. The car is the headline text, usually
just TEXT, but possibly modified if options have been extracted from the
text. The cdr is the sectioning entry, similar to what is given
in org-export-latex-classes. (fn LEVEL TEXT)