Fix capitalization of title for subsection 2.
diff --git a/Doc/lib/libtest.tex b/Doc/lib/libtest.tex
index f53f18b..f807051 100644
--- a/Doc/lib/libtest.tex
+++ b/Doc/lib/libtest.tex
@@ -142,7 +142,7 @@
 \end{seealso}
 
 
-\subsection{Running tests Using \module{test.regrtest} \label{regrtest}}
+\subsection{Running tests using \module{test.regrtest} \label{regrtest}}
 
 \module{test.regrtest} can be used as a script to drive Python's
 regression test suite.