Add PhpUnitMockShortWillReturnFixer to @symfony:risky rule set

Author: kubawerlos

README.rst

@@ -1357,7 +1357,7 @@ Choose from the list of available rules:
   - ``target`` (``'5.4'``, ``'5.5'``, ``'newest'``): target version of PHPUnit; defaults to
     ``'newest'``
 
-* **php_unit_mock_short_will_return**
+* **php_unit_mock_short_will_return** [@Symfony:risky, @PhpCsFixer:risky]
 
   Usage of PHPUnit's mock e.g. ``->will($this->returnValue(..))`` must be
   replaced by its shorter equivalent such as ``->willReturn(...)``.

src/RuleSet.php

@@ -199,6 +199,7 @@ final class RuleSet implements RuleSetInterface
                 'use_escape_sequences_in_strings' => false,
             ],
             'php_unit_construct' => true,
+            'php_unit_mock_short_will_return' => true,
             'psr4' => true,
             'self_accessor' => true,
             'set_type_to_cast' => true,