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

Closes SF bug #724751.

Doc/lib/libcgi.tex

@@ -351,6 +351,9 @@ The optional argument \var{strict_parsing} is a flag indicating what
 to do with parsing errors.  If false (the default), errors
 are silently ignored.  If true, errors raise a ValueError
 exception.
+
+Use the \function{\refmodule{cgi}.urlencode()} function to convert
+such lists of pairs into query strings.
 \end{funcdesc}
 
 \begin{funcdesc}{parse_multipart}{fp, pdict}

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}