MDL-48894 core_registration: minor string tweak

lang/en/admin.php

@@ -801,7 +801,7 @@
 $string['pgclusterdescription'] = 'PostgreSQL version/cluster parameter for command line operations. If you only have one postgresql on your system or you are not sure what this is, leave this blank.';
 $string['phpfloatproblem'] = 'Detected unexpected problem in handling of PHP float numbers - {$a}';
 $string['pleaserefreshregistration'] = 'Your site has been registered. Registration last updated {$a}. You can manually update your registration at any time.';
-$string['pleaserefreshregistrationunknown'] = 'Your site has been registered but the registration date is unknown. Please update your registration using the \'Update registration\' button or enable the \'Site registration\' scheduled task so that your registration is automatically updated.';
+$string['pleaserefreshregistrationunknown'] = 'Your site has been registered but the registration date is unknown. Please update your registration using the \'Update registration\' button or ensure that the \'Site registration\' scheduled task is enabled so your registration is automatically updated.';
 $string['plugin'] = 'Plugin';
 $string['plugins'] = 'Plugins';
 $string['pluginscheck'] = 'Plugin dependencies check';