Add reference link to set types in tutorial #140379, on line 448

Author: dougrandrade

Doc/tutorial/datastructures.rst

@@ -445,7 +445,7 @@ packing and sequence unpacking.
 Sets
 ====
 
-Python also includes a data type for *sets*.  A set is an unordered collection
+Python also includes a data type for *sets* (see :ref:`types-set`).  A set is an unordered collection
 with no duplicate elements.  Basic uses include membership testing and
 eliminating duplicate entries.  Set objects also support mathematical operations
 like union, intersection, difference, and symmetric difference.