Excise the sets module. SF #1500611 by Collin Winter.

Doc/lib/libstdtypes.tex

@@ -1334,16 +1334,6 @@ Note, the non-operator versions of the \method{update()},
 \method{intersection_update()}, \method{difference_update()}, and
 \method{symmetric_difference_update()} methods will accept any iterable
 as an argument.
-
-The design of the set types was based on lessons learned from the
-\module{sets} module.
-     
-\begin{seealso}     
-  \seelink{comparison-to-builtin-set.html}
-          {Comparison to the built-in set types}
-          {Differences between the \module{sets} module and the
-           built-in set types.}					      
-\end{seealso}
      
 
 \section{Mapping Types --- \class{dict} \label{typesmapping}}