For sets with cyclical reprs, emit '...' instead of recursing.
diff --git a/Misc/NEWS b/Misc/NEWS
index 9acc771..7ab30ed 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -18,6 +18,9 @@
   custom ``__eq__()`` method to confuse set internals when class instances
   were used as a set's elements and the ``__eq__()`` method mutated the set.
 
+- The repr for self-referential sets and fronzensets now shows "..." instead
+  of falling into infinite recursion.
+
 - Eliminated unnecessary repeated calls to hash() by set.intersection() and
   set.symmetric_difference_update().