Change the level of a few headings. Remove duplicate title.

pep-0483.txt

@@ -11,17 +11,14 @@ Created: 19-Dec-2014
 Post-History:
 Resolution:
 
-The Theory of Type Hinting
-==========================
-
 Abstract
---------
+========
 
 This PEP lays out the theory to be referenced by PEP 484.
 
 
 Introduction
-------------
+============
 
 This document lays out the theory of the new type hinting proposal for
 Python 3.5. It's not quite a full proposal or specification because
@@ -33,6 +30,10 @@ that can be used in annotations; and finally we define the approach to
 generic types. (The latter section needs more fleshing out; sorry!)
 
 
+Specification
+=============
+
+
 Summary of gradual typing
 -------------------------