org-syntax: Fix lists of elements without affiliated keywords

* dev/org-syntax.org (Affiliated Keywords): Add headlines, property
  drawers and sections to the list of elements without affiliated
  keywords.

dev/org-syntax.org

@@ -122,16 +122,21 @@ Unless specified otherwise, case is not significant.
   :CUSTOM_ID: Affiliated_keywords
   :END:
 
-  With the exception of [[#Inlinetasks][inlinetasks]], [[#Plain_Lists_and_Items][items]], [[#Clock,_Diary_Sexp_and_Planning][planning]], [[#Clock,_Diary_Sexp_and_Planning][clocks]], [[#Node_Properties][node
-  properties]] and [[#Table_Rows][table rows]], every other element type can be assigned
-  attributes.
+  With the exception of [[#Clock,_Diary_Sexp_and_Planning][clocks]], [[#Headlines_and_Sections][headlines]], [[#Inlinetasks][inlinetasks]], [[#Plain_Lists_and_Items][items]], [[#Node_Properties][node
+  properties]], [[#Clock,_Diary_Sexp_and_Planning][planning]], [[#Property_Drawers][property drawers]], [[#Headlines_and_Sections][sections]], and [[#Table_Rows][table rows]],
+  every other element type can be assigned attributes.
 
   This is done by adding specific keywords, named "affiliated
   keywords", just above the element considered, no blank line
   allowed.
 
   Affiliated keywords are built upon one of the following patterns:
-  "#+KEY: VALUE", "#+KEY[OPTIONAL]: VALUE" or "#+ATTR_BACKEND: VALUE".
+
+  #+begin_example
+  ,#+KEY: VALUE
+  ,#+KEY[OPTIONAL]: VALUE
+  ,#+ATTR_BACKEND: VALUE
+  #+end_example
 
   KEY is either "CAPTION", "HEADER", "NAME", "PLOT" or "RESULTS"
   string.