[Validation] fixed a link

bamarni · bamarni · commit a3dc9cb48b3f · 2013-06-17T18:16:46.000+03:00
diff --git a/book/validation.rst b/book/validation.rst
@@ -101,7 +101,7 @@ following:
 .. tip::
 
     Protected and private properties can also be validated, as well as "getter"
-    methods (see `validator-constraint-targets`).
+    methods (see :ref:`validator-constraint-targets`).
 
 .. index::
    single: Validation; Using the validator
