minor #14924 [ExpressionLanguage][Security] role_names instead of roles (wickedOne)

This PR was merged into the 4.4 branch.

Discussion
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[ExpressionLanguage][Security] role_names instead of roles

corrected wrong attribute name

relates to symfony/symfony#40087

Commits
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1707188 role_names instead of roles

Author: javiereguiluz

security/expressions.rst

@@ -42,6 +42,10 @@ Inside the expression, you have access to a number of variables:
     The array of roles the user has. This array includes any roles granted
     indirectly via the :ref:`role hierarchy <security-role-hierarchy>` but it
     does not include the ``IS_AUTHENTICATED_*`` attributes (see the functions below).
+``role_names``
+    A string representation of the roles the user has. This array includes any roles granted
+    indirectly via the :ref:`role hierarchy <security-role-hierarchy>` but it
+    does not include the ``IS_AUTHENTICATED_*`` attributes (see the functions below).
 ``object``
     The object (if any) that's passed as the second argument to ``isGranted()``.
 ``token``