Merge pull request #3058 from xabbuh/fix-build-errors

make target name unique that is used as a reference

Author: weaverryan

reference/constraints/Callback.rst

@@ -25,7 +25,7 @@ can do anything, including creating and assigning validation errors.
 +----------------+------------------------------------------------------------------------+
 | Applies to     | :ref:`class <validation-class-target>`                                 |
 +----------------+------------------------------------------------------------------------+
-| Options        | - `callback`_                                                          |
+| Options        | - :ref:`callback <callback-option>`                                    |
 +----------------+------------------------------------------------------------------------+
 | Class          | :class:`Symfony\\Component\\Validator\\Constraints\\Callback`          |
 +----------------+------------------------------------------------------------------------+
@@ -258,6 +258,8 @@ constructor of the Callback constraint::
 Options
 -------
 
+.. _callback-option:
+
 callback
 ~~~~~~~~