set_test_properties: link to the test properties in the documentation

It was linking to the target properties, this was probably an oversight.

Help/command/set_tests_properties.rst

@@ -20,4 +20,4 @@ See Also
 * :command:`add_test`
 * :command:`define_property`
 * the more general :command:`set_property` command
-* :ref:`Target Properties` for the list of properties known to CMake
+* :ref:`Test Properties` for the list of properties known to CMake