Worked around bug SF #125880: changed the text of three sections that
really nasty TeX source to "bleed" into the PDF "bookmarks".
diff --git a/Doc/ext/ext.tex b/Doc/ext/ext.tex
index 3f9eb96..15ee123 100644
--- a/Doc/ext/ext.tex
+++ b/Doc/ext/ext.tex
@@ -631,7 +631,7 @@
 memory, and this should be checked.
 
 
-\section{Format Strings for \cfunction{PyArg_ParseTuple()}
+\section{Extracting Parameters in Extension Functions
          \label{parseTuple}}
 
 The \cfunction{PyArg_ParseTuple()} function is declared as follows:
@@ -956,7 +956,7 @@
 \end{verbatim}
 
 
-\section{Keyword Parsing with \cfunction{PyArg_ParseTupleAndKeywords()}
+\section{Keyword Parameters for Extension Functions
          \label{parseTupleAndKeywords}}
 
 The \cfunction{PyArg_ParseTupleAndKeywords()} function is declared as
@@ -1030,7 +1030,7 @@
 \end{verbatim}
 
 
-\section{The \cfunction{Py_BuildValue()} Function
+\section{Building Arbitrary Values
          \label{buildValue}}
 
 This function is the counterpart to \cfunction{PyArg_ParseTuple()}.  It is