Add cross-references between urllib.urlencode() and cgi.parse_qs[l]().

Closes SF bug #724751.

Doc/lib/liburllib.tex

@@ -211,6 +211,9 @@ When a sequence of two-element tuples is used as the \var{query} argument,
 the first element of each tuple is a key and the second is a value.  The
 order of parameters in the encoded string will match the order of parameter
 tuples in the sequence.
+The \refmodule{cgi} module provides the functions
+\function{parse_qs()} and \function{parse_qsl()} which are used to
+parse query strings into Python data structures.
 \end{funcdesc}
 
 \begin{funcdesc}{pathname2url}{path}