Add a debug assert for org entities being sorted.

org_mode_samples/greater_element/plain_list/affiliated_keyword.org

@@ -1,5 +1,5 @@
 #+NAME: a
-#+caption: b
+#+caption: b *lorem* ipsum
 #+results: c
 #+headers: d
 #+header: e
@@ -12,4 +12,18 @@
 #+tblname: l
 #+attr_latex: m
 #+attr_html: n
+#+NAME: aa
+#+caption: bb *lorem* ipsum
+#+results: cc
+#+headers: dd
+#+header: ee
+#+label: ff
+#+plot: gg
+#+resname: hh
+#+result: ii
+#+source: jj
+#+srcname: kk
+#+tblname: ll
+#+attr_latex: mm
+#+attr_html: nn
 1. bar