Add versionadded marker for ctypes.c_bool.
diff --git a/Doc/lib/libctypes.tex b/Doc/lib/libctypes.tex
index e1a1719..b782fdc 100755
--- a/Doc/lib/libctypes.tex
+++ b/Doc/lib/libctypes.tex
@@ -2298,6 +2298,7 @@
 Represent the C \code{bool} datatype (more accurately, _Bool from C99).
 Its value can be True or False, and the constructor accepts any object that
 has a truth value.
+\versionadded{2.6}
 \end{classdesc*}
 
 \begin{classdesc*}{HRESULT}