Bug #1536828: typo: TypeType should have been StringType.

Doc/api/concrete.tex

@@ -580,7 +580,7 @@ parameter and are called with a non-string parameter.
 
 \begin{cvardesc}{PyTypeObject}{PyString_Type}
   This instance of \ctype{PyTypeObject} represents the Python string
-  type; it is the same object as \code{types.TypeType} in the Python
+  type; it is the same object as \code{types.StringType} in the Python
   layer.
   \withsubitem{(in module types)}{\ttindex{StringType}}.
 \end{cvardesc}