doc: fix hgroup usage examples

doc/sources/admin/rules_examples.rst

@@ -34,7 +34,7 @@ attribute you see there can be used in a rule!
    $groups =~ /\b(?:admins|su)\b/ # admins OR su
    $groups =~ /\badmin_[1-3a]\b/ # admin_1 OR admin_2 OR admin_3 OR admin_a
 
-   defined $hGroups{'administrators'}
+   defined $hGroups->{'administrators'}
 
    # 2.0.8 and higher only
    inGroup('administrators')

doc/sources/admin/sfextra.rst

@@ -38,7 +38,7 @@ You can find the configuration for this feature in
 
    -  ``$homeMail`` : this second factor will only trigger if the
       ``$homeMail`` session key exists
-   -  ``defined $hGroups{'admin'}`` : this second factor will only
+   -  ``defined $hGroups->{'admin'}`` : this second factor will only
       trigger if the user is in the ``admin`` group
 
 After adding your second factors, don't forget to add overload