Straighten out some markup.

"boolean" --> "Boolean" (per the style guide).

Doc/lib/libxmlrpclib.tex

@@ -219,10 +219,11 @@ triggered the error.
 
 \subsection{Convenience Functions}
 
-\begin{funcdesc}{boolean}{value, \optional{truefals=(False, True)}}
-Convert any Python value to one of the XML-RPC boolean constants.
+\begin{funcdesc}{boolean}{value\optional{, truefalse}}
+Convert any Python value to one of the XML-RPC Boolean constants.
 The optional second argument supplies a conversion table to be indexed
-by the first argument's Python truth value.
+by the first argument's Python truth value.  If omitted, the
+\code{True} and \code{False} values defined in this module are used.
 \end{funcdesc}
 
 \begin{funcdesc}{binary}{data}